Tony D
-
Posts
9963 -
Joined
-
Last visited
-
Days Won
74
Content Type
Profiles
Forums
Blogs
Events
Gallery
Downloads
Store
Posts posted by Tony D
-
-
FIA Homogolated Dimension is 35mm diametrical...
-
-
"I can't see anything more then 350hp at the wheels from a race 3.1L"
Then son, you need to open your eyes!
To be pedantic: No you don't need dual staged injection, you aren't going to make enough horsepower to require it. I thought I said that right off. 720CC injectors will run fine. It's not the injector, it's the circuit driving them and it's ability to control it.
-
How clean do you want it to be, do you plan on running around with the plastic covers in the back of the car removed? Nobody will ever see it. Get the hammer. A big one. Make it conform unmercifully. (See related post "Are we too Cocky?" in Non Tech...
) -
Does my 'tap test' work now?
-
"If you have the time to post something negative, you have the time to post something helpful."
And
" do not see a problem with saying "You need to re-read the rules that you agreed to follow. Until you can properly use basic skill of the English language then you won't get any information." Something along those lines. I hope you understand what I am getting at here? "
The problem is people DON'T GET IT! There will be people who, if responded to with the former selection will TAKE IT AS NEGATIVE.
I have said this for over 10 years at another site. People come to a site many times with a chip on their shoulder trying to prove something. Unless they get EXACTLY what they ask for, it's TAKEN as a NEGATIVE.
The total point here is that without NEGATIVE FEEDBACK a child (and they come in all ages) will NEVER SELF-CORRECT.
And longtime member will know a negative response is ALSO A TEST.
If the guy cops attitude, he's not here to learn he's here to make a stand, and make trouble.
We don't need it.
I can't count the times some old bastard looked at me and said 'get out of here, we're busy'...
AND I DID.
But I came back, many times to hear 'What the f* do you want, why do you keep coming around here, we work for a living---GET LOST KID!'
But on the THIRD DAY, Friday night around quitting time, those same guys were all sitting around having a beer. "Kid WTF do you want? Why do you keep coming around here."
Well sir, (sir! SIR!) I've got this problem with my Corvair, and I can't figure it out.
"Corvair, huh? WTF are you doing driving one of those old things?"
I like it, you don't see them any more. They're good in the snow. Everybody told me the only people who know anything about these cars any more work here, so I came to see if I could ask you to give me some ideas on where to look and solve my problem. I looked in the GM manual, but it doesn't really address this issue.
"What manual you got?"
The car is outside, it's in the back seat, let me get it.
(They follow to the door of the shop, and have a conversation while I'm getting the FSM)
I come back, and they see I'm using the GM 1966 Service Manual.
"Well, lets take a look--start it up and lets see what we find."
That was 5pm.
By 11:30 it was "shite, my wife is going to have my a$$ kid! Look, that should get you going do this this and this and if you still have problems come by again next week about closing time and we will see what we can do. Every third Saturday we are in here on our own time and doing side jobs...if you want come by then and we can get it up on the lift for a bit longer and take care of this other stuff here"
What do you think the response would have been on Friday if during the first two brush-offs I flipped them off, called them old a$$holes, and maybe kicked the garbage barrel over with you youthful petulance?
This is no different. There are tests to get into anything. If you think you are beyond it all, that you are somehow special and shouldn't undergo the same tests trials and tribulations that countless millions have already undergone...maybe you need to think less of yourself and respect the time and effort of OTHERS MORE!
And that is what it comes down to: show up here thinking you're OWED anything and you will have a rough time of it.
If you want a real good approximation of what that interaction was like (above) I suggest you rent the movie 'Christine'---the guy in the Junkyard "this place is for working stiff gotta keep their cars running to put bread on the table, any sh*t from you and you're out on your a$$!" I almost cried when that scene played because it could have been Herb. Yeah he had a rough as hell exterior, but it's the way he was, and if you just didn't give him sh*t, he opened up his whole world to you. Herb died some years ago and you would be amazed to know how many younger mechanics took their time off to drive across the state and come from out of state to attend his funeral. Sometimes all it takes is realizing you aren't the most important thing in the world, and you get some great results from people. Another example is the Clint Eastwood Character in 'Grand Torino'---plenty of those guys around when I was growing up. Kids today watch the movie and see 'racist old ass' but when you WATCH and SEE what the character is going through, what he's experiencing you realize appearances are deceiving. The turning point in Gran Torino was when Toad helped the old lady with her groceries, and that his parents (as it were) forced him to come apologize for what he had done.
Until the oldtimer sees that spark, that willingness to humble yourself and assists someone else, they didn't give a rats-ass about you. The thing about respect is it's not necessarily the guys you give it to that determine what responses you get. Many times it's the people you DON'T give it to when others are watching that puts the nails in your coffin!
-
Our initial testing was done on open headers and the header was optimised (including the header collector) to get best HP under the curve. After that, we grabbed the largest pipe we could fit under the car and still have ground clearance. We wanted as little flow restriction as possible after our tuned header collector combination. We didn't run the 2.8 with the belly pan that often, only two classes, and with the hassle of installing / removing it we concentrated on open header performance.
The exhausts collectors were 2.5" diameter, and we couldn't make megaphone 2.5 to 3" transition pieces fit due to the angles involved, so we concentrated on mandrel bent 2.5" tubing with as little bending as possible to get the turbes to exit the back of the car. I think our backpressure under full load at full rpms was less than 4" W.C as I recall...but this was 10 years ago. It was near nothing. We could not explain the 20HP drop with such a low restriction other than there had to be some sort of anti-reversionary effect of dumping the exhaust pulses out of the collector which scavenged better than dumping it into a tube. We theorized for a while about putting 4" sections on a stub of 2.5" piping then merging in the horizontal plane by the tranny to the 2.5 out to the back...but that was not to be. We made our record and stuck with what worked.
Running the 2 liter on headers with primaries that were (I forget now exactly) 2 or 3" shorter than the L28 we did not experience the loss in the same piping. Hookup was identical almost all the shortening of the pipes was done in vertical header primaries, so the exhaust just 'tucked up higher' than previously giving us slightly better ground clearance at the transmission bellhousing area. That it worked on our existing piping and we didn't have to make a completely new set to run out back was an unexpected plus that went along with not losing any HP!
-
No, increasing tension with a spring only masks a poor technique, and overstresses the linkages.
The car ran fine without a spring from the factory it shouldn't need one now!
A spring is a band-aid for poor technique, or a binding linkage someplace.
Fix the problem not the symptom! There are tens of thousands of cars on the road like this that operate just fine without an additional spring.
My triple setup had only the stock mikuini spring on the crossbar to return the linkages to stop. Many people were 'amazed' at how light the throttle pedal was---"Like a stock 240 with SU's!" Compared to many people with 40# of spring pressure to keep their throttles closed becuse of boudn linkages, linkages that were misadjusted, poor over-center design on their 'modified' bellcranks...
In daily driving a HEAVY throttle pedal will become TIRESOME. Take if from me, you DON'T want a heavy throttle, when you get into a car with a properly designed silkysmooth throttle pedal you will continually brickfoot it and never get the hang of throttle modulation.
A spring is not the answer, and it is 'NOT' how you adjust a pedal speed movement issue! Look at ANY OEM throttle setup and see how hard they work to NOT put additional springs on their setups. MECHANICAL LINKAGE that self-returns to idle WITHOUT SPRING AID (this does not include at the carburetor where a throttle return spring is mandatory) is the SAFEST setup there is. If the linkage breaks, the carbs will return to IDLE.
If you depend on a SPRING to control the LINKAGE, if it breaks there is a chance the T/B will NOT go back to idle on it's own and you are up sheets creek without a paddle my friend.
Properly engineer the solution, don't band-aid it!
-
So then the condenser was NOT related to the injectors opening and closing...
-
If you go with ITBs, manifold velocity will be less important when compared with carburated engines. That is another advantage of port fuel injection, you can have big runners that promote flow yet fuel delivery is not affected as it would be with a large-manifold, carburated engine.
That is true to some extent, but the more velocity the better even in ITB's. The atomization is taken care of mostly by the higher pressure injection through the nozzle, but the higher volocity acts the same way for homogenizing the mixture same as with a carb. "port injection" is more for emissions purposes---real high performance injection has the injector in the air horn, or throttle body, and the manifold is still 'wet'!
The thing ITB's give you is that you don't need to RESTRICT the airflow through the ITB body to PULL fuel into the airstream (venturi and jet well arrangement)--therefore they flow better. You INJECT the fuel atomized, and the higher velocity airstream you inject the fuel into---the better results you will have in mixture homogenity!
ITB's flow better (SCADS BETTER) in the SAME runner than Carburettors for this reason. Carbs are usually measured at 28 or 14" mercury restriction. EFI at 9". The flow increase for the same runner size is astronomical. With ITB's you don't NEED larger runners. The above statement has it exactly backwards---CARBS need the big runners for flow because of the inherent restriction needed at the front end. They then taper radically from carb to intake to keep velocity up.
In an ITB, they are smaller by a factor, and need not taper as much because they don't start out as large. They operate at less differential, and therefore flow more for the same size port.
The Bonny car gained 40HP and 700rpms of operational speed when going from 45 Webers to 45 ITB's--same head same cam, same manifold. And that head went on our 2 liter and has run to significantly higher rpms. The Webers idled at 1700 rpms to keep running relatively smoothly. The EFI would idle wherever we wanted it to, from 400 to 1700rpms. WE normally idled it at 900 just because.
-
The difference is how the regulator is supposed to regulate.
Some are merely restrictions, bascially a check valve that opens at a preset PSI to hold pressure there downstream. These are not really very accurate, and as they are actually a restriction to flow, could cause an issue if they fail by totally shutting off fuel to the engine.
Some are 'backpressure regulators' meant to restrict the fuel returning to the tank---this keeps the fuel pressure AT THE CARBURETTOR consistent regardless of drops between the pump and the carbs. This is preferred. If your fuel pump starts clogging, this type of regulator senses the pressure drop and closes off the return allowing more fuel to the carbs to keep fuel pressure constant.
As long as the fuel pump has sufficient volume and pressure capability to flow through the restriction, you will have consistent fuel pressure at the carbs. I used an OEM EFI pump for my fueling for years, and at times my nasty tank plugged the fuel filter pretty good, but I could still get proper fuel pressure at the carbs.
I'd get a GOOD GAUGE (not one from a mass marketer, something like a fuel pressure testing gauge---many vacuum gauges for idle vacuum will test mechanical fuel pressure to 7psi as well) and compare THAT to what you see on the gauge.
Like someone said, is it causing performance problems?
Many times you will see pressure go up after shutdown then drop to zero as the bowls boil out and the floats drop relieving fuel pressure in the line.
Dont' konw which facet you hvae ,but it's not uncommon to have to run three of them on a serious engine to supply fuel. For a stocker with carbs it should be O.K., but at higher rpms under load it may fall short especially if you have a restrictive regulator and not one on the return line.
You may want to consider regulating the return line from full size to some smaller diameter by installing a jet in it---say 0.050" or whatever and see how that affects your fuel pressure. If you can put the jet in the return line so that it's not over 4psi at idle (with your fpr set to 3.5psi) then that is all the return line area you will need. This will help on high end fuel pressure loss under load as unrestricted return lines can rob fuel from the carbs when the floats fully drop.
Good Luck.
-
Threaten to turn them in to an interstate commerce regulating body for bait-n-switch.
Many states have laws regarding posted prices versus what 'scans' at the register.
If enough people MAKE them honor their pricing through threatend reporting to regulatory officials, perhaps they will be a little more proactive on updating pricing, or make a more prominent CALL FOR LATEST PRICING disclaimer on each page.
Don't know until you try, what's the worst they can do, charge you what they were going to charge you anyway?
-
Spray the suspect areas with a mist of water from a sprayer like for houseplants. If the noise changes or the engine speed changes you found your prospective leak.
Is this an EFI car with CAI? Lots of times the intake noise is appreciably higher with that modification than when going through the stock breather box. Not a lot of specifics, so it's all guessing! Sorry.
-
Driver error, refine technique.
Otherwise, bellcrank pivot arcs will do a lot to change the linearity of the movement. But generally, with a stock clutch plate (you did not specify metallic clutch) this is a driver finesse issue with brickfooted throttle and clutch usage.
My turbo car had throttle cable actuation to triple 44mm carbs on a blowthrough turbo running a 9# flywheel and a metallic clutch running through a 3.7 rearend. I could drive it all day in LA stop - n - go. My wife HATED it because 'it had an on-off-switch throttle' and REFUSED to drive it.
She could not master the pedal finesse. This is a driver issue, not an equipment one. Especially if you are on a stock rearend and organic clutch facing! Stock weight flywheel? DEFINATELY a driver throttle modulation clutch engagement learning curve issue!!!
Turbos make torque even when not showing boost. It drives different than the old engine, get used to it. That's why the swap was done. If the throttle is STICKING (as they sometimes do) then fix that, but the linkages are the same on ET and any other EFI or Carbbed Datsun. It's just a matter of controlling your foot. Try driving in wrestling shoes and see if it's any better than CAT Workboots (seriously!)
-
I read things like large injectors are hard to control at low RPM, so you run the smaller set like you said for lower RPM and switch to large ones after a certain point. For my N/A application, my largest injector would be 450-ish I think I saw, for a 3.1L 8000RPM max therefore I wouldn't need 3 injectors since the gap between my smallest to the biggest isn't that big...?
Don't believe everything you read. For a race setup, especially with a large cam with lots of overlap, alpha-n is the easiest way to go. Guys with tuning problems are running on the street and lugging the engine below the point where there is a good vacuum signal for the MAP sensor.
For an engine like that the old TEC2 by Electramotive had a 'PAFZZ Blend' software package that let you run alpha-n at idle, and then blend the mixture of pure throttle position/engine rpm based fueling into a MAP based control once the RPMs got high enough and the cam made vacuum. This makes even the wildest of cams run smoothly---we could idle our Bonny engine to 400rpms using it. Bang Bang Bang Bang... thought the engine would die, but it would tick over reliably just above the cranking setpoint of 300 rpms like clockwork. Try that with carbs of MFI! Our 45 Webers wouldn't idle reliably with the same cam below 1700rpms, a centermount four barrel wouldn't idle below 2200 rpms. Power came on aroudn 5000 and pulled above there, with the engine really liking it above 6K.
With a cam like that, you have to select the right gear for the corner and know how to drive to keep the engine making power. With a 3.1 it may have more bottome end, but it won't have idle vacuum if you are contemplating the cams you discussed in another thread. And that really puts you into Alpha-N control for the reliable off-idle (even if it is 1700 rpms!) ability to get the engine accelerated without bucking and spitting.
Thing is, with EFI you can blend Alpha N and MAP based control techniques. With MFI you will always have Alpha-N---it will always be based on continually injecting fuel based on a fuel pump that makes flow and pressure based on engine rpm, and a bypass pressure control (that dictated volume through the nozzle) that is solely based on throttle position. Hillborn and Kinsler do make some vacuum anneroid items that allow it to drop pressure a bit under vacuum conditions and lean out the setup at partial throttle, but again that is another mechanical tuning process. It all seems so easy at forst because it's mechanical. But when you get into it, the more you want, the more adjustments you have to make. And in the end every mechanical adjustment is subject to plugging with dirt, loosening and changing, or simply downright failing when a spring breaks or takes a set. With electronics, it's the exact same process, except your hands don't get drenched in methanol and crack from lack of skin oil, you simply arrow up or arrow down.
The largest issue people have with tuning EFI is they don't understand what an engine does or how it really works. Once you realize what the engine needs, the tuning becomes logical. Then it's a matter of doing the tune one portion at a time. It's just easier for me on EFI because I can do it FASTER than having to take something apart, reassemble it, then go test.
It's my ADDHD side. I can get instantaneous feedback on what the adjustment did with electronics---and therefore go in the right direction faster.
If you have ever had to tune PID loops on industrial controllers you will understand what I mean. Oldtimers used pneumatics. There were kids who HATED pneumatics because of the constant hassle of calibrating them every quarter, they were subject to dirt, water in the air, etc... And tuning them was a chore. But old timers would come in and seemingly twist the dials like crazy and in a few adjustments be finished. They knew that changes on mechnical devices needed to be radical so you knew right away which way you needed to go. Once you knew that, you make fine adjustments. Kids usually took the opposite approach tuning in fine increments and never seeing a change---then it just 'went haywire'... Same oldtimers usually picked up on electronics and found the same techniques worked there as well, just punched in numbers instead of twisting dials. Double the Porportional and see what it does, double it again till it's in Hystersis, then go back 50% from where you were. Same for Resets a minute. BIG changes and then fine. I watch guys make 10 or 20% changes all day playing around with electronic tuners on our equipment to no avail. I go in there, go from 150% to 450% then back to 275% and BANG done. They can't figure it out. I tell them, it's a LONG way from 150 to 275 at a 5% increment when you have to WAIT HALF AN HOUR between adjustments to see if it worked.
MFI is like old Pneumatic controllers--they work almost as good as electronics, but you have all the pittfals of mechanical devices. If it gets dirty, it poops, if it's hot, it may poop. If it's loose it poops. If the thing is too tight it poops. And every time it poops it's 30 minutes to get it back to where it was.
With electronics you eliminate a lot of that. Sure there are electrical stuff that can screw with you, but on a race car especially there is no great electric load, so power should be good. Wiring should not be an issue as it's all dedicated. What it ends up coming down to is what the class rules dictate. If they allow EFI I would run it over the other choices. If they mandate 'period correct induction' I would haul out photos of the 1971 240Z running EFI on ITB's and argue like CRAZY for it to be allowed (and really piss off the Porsche guys who were running Kugelfischer MFI!)
If it came down to it, and you have never worked with MFI before, this is likely not the best place to learn! I would tend to run the Lucas Slide Valve system as it was OEM available on many cars in Europe, and has refinements for running in mid throttle. It will be a more tractable system than a Hillborn, IMO. But finding one and setting it up will not be a cheap prospect. I would tend to steer you towards carbs (big ones) but with the cost involved in them you're into EFI teritory.
Again, the reason we went to Tec2 and TWM ITB's on the Bonny car was that a new manifold and set of 55 Webers (which is what we needed to get the horsepower we wanted) was going to be as much as the EFI setup. And we would still have a damned distributor! What sold us was the ability to control timing precisely...and in the end that will KILL a high rpm engine. A couple of degrees of spark scatter at 8000 rpms and you detonate. Bang. Done.
Even if you run carbs, I would SERIOUSLY recommend you get something like an Electromotive HPV1 Ignition setup and eliminate your distributor entirely as a source of failure. SCCA even now allows this from what I'm understanding. But if you can program that, you're well on your way to mapping fuel.
As for injector sizing, you have to keep your injector pulsewidth within the available time of the valve opening (usually). This means larger than you think injectors so they can deliver the fuel with a shortest pulsewidth available. At 8000 rpms we are running 550cc injectors on a 320HP engine. And the same injectors worked perfectly on the 2 liter making 2/3's that amount. The 'control at idle' is terribly subjective and many times the interweb is bogged down in myths, legends and people who put to much goddamned emphasis on THEORETICAL arguments. Yes, fuel puddling can occur. In practical application does it make a difference???? For them it will be something to rail on about everytime they see an 'oversized injector applied' and out comes this argument or that. But in reality there is little to no PRACTICAL effect to the phenomenon (whatever they may be railing on about) and you can disregard the bluster. It just becomes hard to know what is what sometimes.
I watched an unemployed guy (acquaintance of mine) walk into a successful well known Datsun Restoration Shop in SoCal, and after he looked around a bit, he said to the owner...his FIRST words to the guy were: "What you gotta do is..."
A guy who's UNEMPLOYED, NEVER ran his own business, NEVER ran a restoration business, NEVER EVEN FINISHED HIS CAR (been sitting in primer and bondo since 1986!) deigns to tell a guy with 11+ years as a successful operating business how he needs to straighten up his act and fly straight.
These are the guys on the internet arguing points that in practical application have no real meaning or affect. Ask them what they run, and when the reply starts "I read" throw it out, or ask for references so you can read it yourself. Usually it's a reference to someone else who "read" somewhere that something could maybe cause a problem when the moon aligns in the 12th trimester of a pregnant elephant that kneels on the Mekong Delta to get a drink of water while a monkey poops from a vine swinging nearby... Like that happens all the time right? Yeah, that's real applicable to me and my Datsun.
Some of the Bob Sharp cars did use MFI BTW... Wonder where those setups went...
-
Port matching got a BIG NAME from DOMESTIC heads where the ports are misaligned and in some cases the gasket blocked half the port, or were off by hald the cross sectional area.
In an old Chevy, port matching is almost MANDATORY because of the piss poor casting alignment.
This ain't a Chevy. They don't need an overhaul at 100K. They don't need manifold port matching. They don't need ridge reaming.
Let the domestic myths die!
-
1
-
-
Argh...
The manifold needs to taper from the throttle plate to the back of the valve.
This can't happen when they are 'gasket matched' in the traditional sense.
Can we stop using the word 'port matched' or 'gasket matched' now?
Proper inlet manifold will taper from the throttle plate to the back of the valve. The mikuini manifold will allow you to do this and the larger ITB you use the more the veolocity will increase as the taper will be more over a shorter distance (to a point.) A longer manifold would only mean any matching would mean a more gradual blending over a longer distance...
As for being a MOOT point with ITBs... It is because GASSKET MATCHING IS USELESS THE MANIFOLD NEEDS TO TAPER FROM THE BACK OF THE THROTTLE PLATE TO THE BACK OF THE INTAKE VALVE CAN WE PLEASE STOP USING "GASKET MATCHING" AS A TERM NOW BECAUSE GASKET MATCHING DOESN'T WORK!
In terms of the reversionary step, NO, this will still be true. The intake manifold will benefit from being slightly smaller than the intake port in the head.
The key is unless the manifold continually tapers from the throttle plate to the back of the intake valve you are FAR BETTER OFF having a smaller intake manifold so you have the reversionary step than to make it the same size. If you are not willing to properly taper the manifold to match the port in the head, then LEAVE IT ALONE. Hogging out 2" of port for the sake of making them even is useless and a waste of your time. You will GAIN nothing, and likely will hurt reversionary tendencies of the setup, if not overall flow.
-
I don't like people demanding 'respect'--- it's not a give-get relationship.
You don't come into someone's house and make demands on them. Regardless if you take off your shoes and don't fart in the living room!
Respect comes from interaction, and proving yourself to a group. I can think of some threads active now where people's prior posts are having a deliterious effect on their current posts. But it's because they continue to post in a similar fashion as their first attempts.
There is a learning curve. And nobody here should have to 'wait while you get up to speed'...
As has been stated, there are many here who started (myself included) who read the site pretty completely before even posting the first time. If MORE people would do that, the 'lighten up' attitude would not be necessary.
Most of the people I have met from this site are VERY laid back and helpful. Problem is they don't really have a lot of time in their personal lives to waste. And coming to a site, not reading and abiding by the rules, and posting repetitive questions which clearly could be answered by expending only a modicum of effort and READING A LITTLE BIT wastes their time.
So you come in the house and take off your shoes outside. You don't fart in the living room. But you cop a squat and take a dump on the new white carpet in the living room.
I may laugh, but I lay money someone who will have to CLEAN IT UP is going to be PRETTY PISSED OFF!
And that is what it comes down to: MEMBERS on this site may 'flame' a noob, but it's out of respect for the MODERATORS who will EVENTUALLY have to come and CLEAN THE NOOBS MESS UP!
WITHOUT the support of the BODY OF PARTICIPANTS, the uphold a culture of excellence and decorum, the moderators will have to continually delete posts, move posts, and generally WASTE A LOT OF THEIR TIME (time which, I personally, would rather they have to spend answering questions on discussion forums, for example...)
You can see the loss of a cohesive culture at another Z Site. The BODY just couldn't understand why people were so harda$$ed. And it got to a point Moderation didn't have a CHANCE IN HELL to rectify the situation.
Instead of thinking of YOURSELF, think of the MODERATORS and their job. SURE, to you and me that noob may be hilarious, and 'what's the harm' but SOMEONE WILL HAVE TO CLEAN IT UP afterwards to keep the site tidy and readable.
In the end, that is what it really comes down to! You and me, we can laugh about it. But they will have to clean it up. If I had to clean up someones dump on my clean white carpet, I might react a little heavy handedly from time to time to make and example that the rules need to be followed: "Don't wear your shoes inside, no farting in the living room, and no defacation outside the privy." It's not hard rules to live by, I guess it's just a little peanut and corn poop, let's just overlook it this one time, shall we? What about it guys, give the noob a break.
(The voice of Walter resonates within me...it speaks to me...it compels me...)
-
Anecdotal Dyno Remberances:
L28 on Bonny car lost 20 HP when we bolted on the full exhaust needed to run the full belly pan. TWIN 2.5" exhausts. 8500 shiftpoints.
on the same dyno...
L20A did a baseline tune without the exhaust same as we did for the L28, then hung the exhaust in anticipation of having to reconfigure the map slightly to optimize for the restriction of the exhaust. We lost no horsepower, and ran the test several times because this really surprised us. As a result when we run the 2 Liter engine we ALWAYS run the full exhaust for the reasons John C mentioned, the car is WAY quieter with the rear exit exhaust.
But with the L28, 20HP is 20HP and if we don't need to run it, we won't!
Conclusions:
For a 2L engine pumping to a shiftpoint of 9500 rpms, headers and a twin 2.5" exhaust did not change our horsepower at all.
For our 2.8 L engine running to only 8500, that same 2.5" twicepipe system costs us 20HP (it was more before the fuel and timing maps were tailored to the different exhaust characteristics.
So the 'nothing is 'too big' argument' I would tend to agree with---but the size of tubing required for an exhaust to NOT drop ultimate horsepower is far larger than most people would think!
There are other considerations, but I was personally shocked to see our drop running twin 2.5's. I figured that would be PLENTY of flow. It is, in a sense....but only for a 2-liter!
-
Follow the links, they sell components and total systems.
Nothing you do to the carbs has to render them unuseable on Rick's conversion.
It's all pretty well explained on his website.
As for GMTBI injectors, don't have a clue, but generally most of the V8 stuff will supply more than enough fuel for anything we would produce N/A. The added plus is you don't need extreme high pressure fuel to run them!
Follow the links I gave and snoop around his site and FAQ's. The guy from France posts here, and posted his SU conversion when he had it installed. It's in a 240 and has been runing for over a year or so.
-
You totally missed the point---your tire is getting to the point that it will GET CUT if you actually get that POS running right.
Being on the throttle and having a blowout on the rear, under power, at 100mph is not a pleasant experience.
Fix the movement of the trailing arm or clearance your wheelwells! It's an ACCIDENT WAITING TO HAPPEN. If you actually get the engine running CORRECTLY, I posit as the movie title read: "There Will Be Blood"
-
Making excuses won't make it happen. The building of an air filter or airbox will be equally as difficult on a carburetted car as one with injectors shooting down the former carb throats.
If you can picture this, standard Bosch Injectors of 550CC size mounted inside the stock 73 Flat Top air cleaner supplied and regulated (with a 280ZX stock FPR INSIDE THE AIR CLEANER ITSELF!) without any untoward perforations noticable to the casual onlooker.
If that can be achieved, punching two holes in the back plate of an ITG air fliter for fuel in and fuel out doesn't seem all that difficult.
The secondary injectors on there are because TWM is mounting supplemental injectors for higher rpm usage. Or for methanol injection. Or for whatever reason. I know people with a set of 370CC injectors at the head which runs from idle to 3000rpms. Another set of 550CC injectors that run from 3200 till fullboost and to around 6000rpms. Both sets shut off at 7000.
That's when the third set of 1100's kick in for the trip to redline.
TWO computers, one controls the first two sets, and the third runs a totally different computer which is totally RPM / Boost / Throttle Position based. Ignition timing is handled by the first computer through the whole RPM range.
And you're worried about throttle position and rpm based fueling only? It's entering (on a megasquirt) values on an 8X8 matrix. 64 bins. 144 if you choose the 12X12 bin setup. It's far easier than you think it is...
If you let your fear limit you, you will remain limited!
-
SU TBI ADAPTERS???? You don't say? Like this?
Patton Machine, if you want to use the GMTBI Adaptors. Proven quantity, running in France on one car WITH GM ECU! Should be photos out there of them installed.
Wonder Who Supplied the Hitachi Bodies as Prototypes?
YEAH, THIS ENGINE IS FUEL INJECTED!!!
Amazing what some tubing and routing of wires can achieve in the form of illusions, eh?
-
No, I meant EXACTLY what I said. Read it again and the logic behind the statement.
IF the MANIFOLD is SMALLER than the port in the head, the resultant STEP exists in a REVERSE-FLOW direction, which will stop intake tract REVERSION during the overlap portion of intake open/exhaust open valve events. The flow on the manifold is PROVEN to give a 22% bump in performance to an L24 AS-CAST (that was with 44's not 40's). That means WITH THE SMALLER THAN HEAD PORT ON THE MANIFOLD SIDE. You open it up and 'port match' it, you gain NOTHING. Most people have realized 'port matching' in a Datsun head is wasted effort and that a small step as exists is BENEFICIAL to low speed operation. Cut that step out by match porting, you LOSE this benefit.
IF the HEAD side is SMALLER than the Manifold Port, there will be an impeding of the airflow caused by the bump.
If the HEAD side is BIGGER than the Manifold Port, there is a 'check valve' action during overlap, and no real impedance to flow whatsoever.
If they are MATCHED in size, you have no overlap anti-reversionary step, making for worse ariflow, and chances are that the porting will not MAINTAIN a taper from throttle plate to valve. It will OPEN UP in the 'match ported' region, and then begin to taper again in the head. This is TERRIBLE for flow, because it kills velocity.
There is absolutely NOTHING wrong with using the Mikuini Manifold AS CAST on a non-ported head.ESPECIALLY without a cam!
Remember this is how the thing was DESIGNED AND TESTED! NO PORTING OF ANYTHING JUST BOLT IT ON! Jetting was the only thing open for change depending on trackside conditions.
Mess with it, and chances are unless you taper that intake back almost to the throttle bore you will make the flow through the manifold and into the head worse than if you just left it alone and drove it!
)
Mikuni 40phh intake runners
in Fuel Delivery
Posted
Port injection is a compromise for Emissions, don't kid yourself.
Runner velocity is critical in either application. Making it sound like it's something you can pooh pooh because it's injected at the port is poor judgement IMO.
Most ITB's will inject not at the back of the intake valve, but in the ITB itself, and all testing has shown the further away the mixture is injected the more power it will make. If you want low end drivability, you keep velocity up.
That is why carburettors always seemed to suffer when sized for maximum power, there just wasn't enough velocity nor manifold vacuum for them to function properly below several thousand RPM's.
If you port inject, you are giving up power under the curve in a big way. If you inject at the TB you aren't giving up any drivability if you have a proper runner design.
Like I mentioned, we gained BOTH drivability, idlability (?) AND top-end performane going to EFI from carbs on the exact same head, intake runners, and etc We simply replaced the 45 Webers and went from a low of 1700 for idle, to anywhere we wanted from 400 to 900 for warm idle. We gained 40HP and somewhere around 700rpms on the top end, power peaking now at 8250, and shifting at 8500 instead of a power peak of 7500 and shifting at just before 8000. Torque curve was flatter, broader, and higher.
We had good velocity before, with the ITB's injecting in the body we picked up all across the board. Our pumping losses decreased quite a bit not having to draw through those venturis.
And we did have an anti-reversionary step at the head/manifold juncture---it was NOT 'match ported'...