Tony D
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Posts posted by Tony D
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My box had the air coming in from the fenderwell side, with a diffuser plate that went lengthways, kind of like the SK Comp Turbo box you had pictured earlier. You would vent from the inlet side of the diffuser, while the carb throats would draw from behind the diffuser plate. Like I said, I drilled holes at the bottom of the diffuser plate to let the air flow underneath it, and diffuse through the little (er, 3/8" 10mm, but LOTS of em!) holes to the main chamber on the carburettor side. This box worked REALLY well compared to the straight 2X4 plenum bolted to the front of the carbs that I later (stupidly) changed to...and I thought it was some sort of 'upgrade'! LOL I wonder how atrocious the flow is in a 2X4 straight box...yeech!
Anyway, my box the air entered the center of the plenum through a single hole (the HKS box shows that maybe 2, 2" holes are better) pointing at the diffuser plate that was angled around 60 degrees inside the plenum which was 2.5 to 3" deep (as I recall, it's 2200 miles away right now). On the bottom of the diffuser plate, about 1/4 of the way from the bottom of the box (which I believe was 5 or 6" tall, and roughly 24 or 28" long) the diffuser bent toward the front of the box---it was bolted with a 1/4" stiffener at the top and bottom to the removable front cover, and there was a flange about 3/8" wide on the box where I used like a million M6-1.0 stainless steel metric bolts to hold it together under the tremendous pressures I was planning to run (yeh...) I believe in this instance, a photo would be worth 1000 words.
I think blowing air directly at the carb throats will cause problems, I'd place a segregated baffle in there at least. The whole idea of the box is to allow residence time and let diffuse pressure fill the cavity so the air going down the throats is evenly distributed and without much velocity other than what the engine is calling for at WOT. i might be wrong on that, but it doesn't seem like directly blowing the pressurized air down the carb throats will be too advantageous.
The air in the vent section has slightly higher pressure due to the size holes, as you want higher pressure in the vent section to enrichen the mix through raising the fuel level in the jet well (pressure differential greater than what normally would be there from the venturi effect). This is why the HKS box enrichens under boost with much smaller jets, letting you run 350 HP to the rear wheels and still get 17mpg in daily beat the heck out of it driving down Carbon Canyon twice daily back and forth from Corona to Brea....
Remember MonZster is designing a plenum for EFI ITB's and his goals will NOT be the same as someone running Carburettors. The carb guys will want the difference in pressures to allow for the float bowl air pressure to be slightly higher, and therefore you MUST have SOME restriction to flow before the main plenum area the carb throats draw from. What may be possible is using the EFI plenum, and like your box is set up SHO, running that Carb Vent Line from the super-high pressure inlet piping red-zone just before the box (or at the elbow where pressure 'backs up') that would probably allow sufficient pressure differential that would allow you do 'dial in' the differenital using those variable orifices we talked about some time...(er, valves in the lines to the float bowl covers I think).
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something weird was going on and when I would gas it the engine would feel like it shut off and lose all power until I let off a bit on the gas.
Something similar happens in my wife's 260Z, WOT and it will hit a wall hard, but feather the throttle back slightly and it will pull further till you get the normal 'fuel is running out of the float bowls faster than it can enter' surging.
Unless you got a very capable e-pump capable of forcing 7+ psi through the float bowl needles on the SU's (like the stock mechanical pump does at higher speeds) the float level will change and you start to run lean on SU's on the top end. I haven't solved that...oh, waitaminit, yes I did, I went to EFI! BWAHAHAHAHAHA!
I digress, forgive me for being off topic, 'back to your regularly scheduled programming'...besides it was Coffee's fault I'm in this thread, if I misbehave, blame him!
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Tony! Tony! Damn it! Where is he when you need him?
Here I am, 4 years later, late but with interesting numbers nonetheless:
As verified by the SCTA at Bonneville:
167.158 F/PRO
172.121 F/GCC
173.325 F/GALT
173.059 F/FALT--fuel used was GASOLINE (yeah, you can do that!)
We had F/FCC as well, at a comfortable margin above 170, but were protested and got the record pulled...
Most of these same records are ours at El Mirage and Muroc Dry Lakes as well, though with only about a mile to get to speed, they are around 10-15mph less. These are two-way averages, and in some cases the one-way speed may be considerably higher due to a tailwind, or mechanical distress on the return run... El Mirage and Muroc are one-way dashes, like Maxton's Monster Mile. I have watched events there a couple of times (try to schedule my training at corporate to coincide with the events during the summer--training is in Davidson, north of Charlotte.)
Interestingly enough after all the dustup, we now may be able to run the 2+2 in "GT" class now, and take that as well...
As for photos of Z-Speedos, they are notoriously innaccurate. A Z with stock sized tires will run 4750 in fifth with a 3.7 rear gear and late ZX five speed (stock L26) which equates to 125 mph. The same car with a 3.9 and an early five speed will top out at 5300 (stock L28...er, towing a small trailer...) which equates to around 120 mph. The car photographed at "130" with a late ZX five speed, stock sized tires, and a 3.36 rear gear, in fifth gear (the best scenario possible) 4100 rpms equates to 124mph... Hmmmmm:iospalo:
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I am thinking that putting a TK81 on there and measuring resonant frequencies of the head will reveal what benefit there is from balancing camshafts...
Of course you would need a before and after spectral analysis.
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This is frightening, my series of smaller holes on the bottom of my diffuser plate on the 'Home Made HKS Knockoff Plenum' took that same approach! Like I said, I never actually got to hold the thing in my hand, so I could only guess what HKS did inside the box to diffuse the air after it's hitting the baffle/diffuser plate...I figured best I could do was drill a series of holes equal to or greater than the cross sectional area of the feeding pipe from the compressor!
That looks pretty good! I think the key is to diffuse it through that series of smaller holes. I think the HKS Plenum I have can be easily modified to work that way as well...
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They have a good reputation in the Muscle Car resto market. They are based out of Corona. Very small ECU box as well! Intuitive learning like OEM "short term and long term fuel trim" as well. I liked their idea of the PWM control on the fuel pump using a fuel pressure transducer to allow a returnless fuel supply. Though for now, their PWM amperage capabilities only support their pump to a 500 HP range---over that you have to lag the Fuep Pul ground at the ECU and run a standalone fuel pressure regulator.
The box is VERY small. They are catering to botique sellers, buys that want their own "House Brand" box they package and sell under their own label. This setup is sold be a couple of vendors all with custom application setups (Claude's Buggies is one). I know of a Dyno Shop that is selling these as 'their system' as well, and is very good at tuning and installing them. If you are in the L.A. area and want some names to visit, let me know and I can give them to you for a visit.
Their main distribution place in Corona (address on their website) is pretty accessible as well. Cool bunch of guys there.
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Yes Jeff, the higher horsepower cars seemed to gravitate towards the Type 1 Box---one of mine has holes that are enlarged. I would think the reason they used the earlier boxes was they were available cheaper once the Type 2 came out, they could easily fabricate the inlet plenum from the 'T Log' the Type 1 used for inlet air, and access to the three diffuser holes was a simple matter of taking the front cover off and having at it with a die grinder.
As I mentioned, one of the things they had to do at higher pressures was open the holes up to keep the float bowl from overpressurizing, and basically pushing fuel through the jets---as you can see the kind of pressure differential from upper and lower plenum can indeed cause that kind of problem. But it's a 'good' problem insomuch as you simply run very rich as you over-boost. A broken wastegate would result in you dumping fuel into the engine instead of running lean. Clever, no?
For an EFI ITB setup, I'm thinking you could play with the hole size, as you don't really need the big pressure differential, you just want the diffusion at as little pressure drop as possible.
On carbs, you would want the pressure to be something more. This is the same issue with Modulator Rings...you have to play with their size to fine tune upper end boost enrichment till you get it right.
But hey, 'Carburettors are Easy', right? LOL
Oh, and on most High-Horsepower Cars back then, it was TWIN turbos for the flow, so off the intercoolers there likely would have been a pipe to each entry hole, instead of that single entry plenum casting. Times change and you can get that flow from a single now---so the inlet plenum may need some revision to better suit the entry to the box.
No matter which way you turn it, a 90 degree bend is going to hurt flow. Especially in the tight confines we have in the engine bay in regards to the strut tower...especially if you want to compensate for engine mount rocking (which is not an issue on your car, granted...but for us mortals with pinned stock rubber mounts...the engine may move a bit!)
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THANK YOU RON!
I knew that damn switch did something else! For the life of me I couldn't remember.
Old age (4X... what year is it again? 2008? Oh yeah, 44 this September!) is a bitch. I could remember a lot more useless trivia when I was younger.
Ever watch Bill Murray in 'Groundhog Day' while he watched Jeopardy? That was me when I was 26...same hair, too! LOL
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PYP Prices in So Cal have risen with the advent of some marketing guy realizing selling parts for their scrap value, while making for a brisk resale / salvage business, 'left money on the table' so now a transmission costs you $180, instead of the former $75, and the engine will run you around $250 with all accessories.
Retail, probably double those numbers. Routinely I see L-Engines sell for $450, and the transmissions for almost as much if they are sought after (like an early a-box five speed)...normally a tranny will be in the $250 range. So in SoCal, I'd expect someone to reasonably expect $700 for the pair if bought separately, and probably $500 if bought together.
Separates always seem to sell for more. Pieces parts, you know?
That's why just about any Z-Car is easily worth $500, as long as it has engine, tranny and third member, you can recover costs and make it a 'freebie'.
My wife, of course, does not understand this, and says to 'get rid of the junk in the yard'---hopefully it's all too heavy for her to move while I'm working on the road.
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Yes, I second the ShopVac idea. It will work nicely to either blow low pressure onto the top, or evacuate the area under the form to make the hot drape fit fast and tightly.
Especially that 16HP bugger Home Depot is selling (Emerson Electric Plant shut down, so I don't know where it's made now but it was in the town I grew up in: Menominee, Michigan...which also has Coleman Racing Products...hmmmm, maybe I should move back...)
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That linked to bad videos that I have since sent around... Those guys mudding the 280ZX are a blast. From what I can tell, they ran it into a tree, mudded it, and generally bombed around in the boonies.
The sharp video production skills are nice, but the ham-fisted hilarious attempts at documentation that are linked together on the youtube page make for entertaining viewing. The 280ZX they use sounds pretty bad as well. And they really beat it. I'm going to stop there, before I get in trouble...
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And curiously here I sit, in the middle of the day, no parts, waiting.
In wonderful Brenham Texas, and I realize "Hey, maybe there's a Z_Club Meeting in Houston this week I can attend!" And I see you're the 'other way'...LOL
Off Topic, but the thought just struck me.
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Gaads, shipping to Oz seems a sketchy shot at best. I receive stuff from there quickly enough, but I have had simple bulky items that can't go USPS Air take literally MONTHS to arrive in Melbourne! My mate there didn't know he had a birthday coming in September (replete with Motorsport Auto West Coast Nationals T-Shirt, etc..to give an idea of shipping time!)
And nobody wants to pay UPS/DHL prices on international shipments. Trust me...I just spent $486 American to ship a 9.5Kg Box UPS Air to Davidson NC! Total for all three boxes was just shy of $1300. Yeech! Talk about "unrecoverable overhead" all that got to be covered in the job pricing!
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The original 432 Exhaust is segregated front-to-back, though it 'appears' they share a common resonator, the piping is separated and baffled.
Original BRE and other Nissan-Supplied racers used segregated pipes as well.
Scavenging has as much to do with pipe size and velocity as anything else.
A lot of this kind of discussion is titter and tatter over theoretical points that don't mean anything appreciably in the real world.
Look at it this way: Will 2HP really make any difference on your car for the street? Will you be happy with the sound, and can you live knowing that in a theoretical sense, your exhaust system is not perfect (and which one really is?)
Some years ago, texts decried mufflers. Today, engines designed around mufflers make more horsepower than those without... Things change. Beware!
Sounds good to me, BTW! Then again, I have a 432 Replica Exhaust under mine! LOL
Oh come ON! Guys, only FOUR views? Maaaaaaan!
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Solenoid...
The EGR is disabled when the engine is cold. This is what the solenoid does. Until the engine reaches 120-130 degrees, EGR is disabled by the water temperature switch.
On the 74's, there is a third gear switch, and a speed switch, AND a water temperature switch (vacuum switch that is thermally activated). The speed sensor and the transmission switch complete the circuit to let the EGR solenoid open to allow vacuum to be ported to the amplifier/diaphragm, and the thermal vacuum switch acts as a mechanical block until the engine is warmed.
The amplified and non-amplified EGR's have different switching scenarios.
The later 77/78 had a back pressure transducer and delay thingie in the hose for California to stop tip-in stumble inherent in the lean operating conditions of Cal Calibrated cars, the Fed calibrated cars were richer to begin with so they just had a thermal vacuum valve like on the earlier 74's. Basically, if you aren't pulling at least 2" Hg on the manifold, the EGR will not be open. So any sort of full load condition will stop it from recirculating.
This is all from memory, but it all goes back to the fact that the cars had a plug if they didn't use a switch. What is the manufacture date on your car it is possible someone has swapped parts, you know!
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Original Non-EGR cars (like non-USA) will not have the switch, they will have a plug.
I forget what it is for, but there is another circuit it disables... Cold Start Valve is a thermotime and crank signal kind of thing.
The 1975 EFI Bible shows the Water Temperature Switch, and does not tag it as California Only, but also shows in most of the diagrams and photos a PLUG in it's place---which I what I have seen on Non-Catalyst cars. (Home Market JDM L20E's had EGR from day one, they had stiffer regulations than California at the time!)
There is a harness for it, and a function it does, but other than turning on the solenoid to allow EGR to work...hmmmmmm....
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I agree, the big hulabaloo about eyebrowing the bores is not a 'NOT'. The heads WILL work, but it depends on how the dowels and head are positioned on the block wether or not the valves tag the tops of the bores or not. I have even seen early L24 engines with big-valve N42 heads on them where the valves 'self clearanced' against the block at original crankover, and then ran tens of thousands of miles before anyone found out the valves were (at one time) interfering with the block.
It's more of a 'should' eyebrow the block statement, rather than a positive declarative sentence structure.... Always check interferences before assembly and determine what needs clearancing and what does not. Some may need it, some may not. Do it and you know you won't have a problem.
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Rewiring the stock harness to work with the Megasquirt's EFI controlled relay to switch power on to the injectors is a REAL EASY hack on the stock harness. All the power wires to the injectors come in a big cable which is spliced to go to the individual injectors.
On N/A cars, the resistor pack is the easiest place to make the switch as it comes from the battery in one cable, which you hook to your relay, and viola...done.
Same for segregating and grouping the grounds for the MS to gate them.
Spend some time with the factory wiring diagram, and it will become self-evident.
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He does it because he drives a BMW...make no mistake, we all know what that means!
LOL
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Wasn't Cartech's more like 4X3 or 4X4? It seems squarish from what I remember, as opposed to the rectangular form of the 2X4 Extrusion.
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They use a squirt bottle to spray methanol into hilborn injector setups to get the car started and that works... Once it's fired once, the atomization of the injectors will have the mix carried to the cylinders without much issue.
Aluminum spacer will be more practical, I don't know where you're going to find machinable graphite that will withstand the vibrations without compressing or deforming. Phenolic might work, but with the close proximity to the headers, that's probably out as well. Aluminum is used OEM for a reason, cheap, easy to machine and form, and durable. Think on it a bit, it's easily obtainable as well!
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I did get that cowl hood at the Yard Bryan was a whole $40. I got your message, been busy though. Next time I'm in PHX, I'll carry it along with me.
Did you balance those reground cams before installing them, BTW?
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Keep in mind, the turbo is the first stage of compression, the supercharger he is using was originally designed to feed 3.8L.
With 7psi turbo boost and the fixed 1.5 ratio of the blower you end up with 18psi to the engine, if it all flowmatches. Thing is the turbo can be slightly to moderately undersized as it can overspeed to feed the blower, which in turn feeds the engine. All you do is externally gate the turbo if you run into backpressure issues on the exhaust side. But with the turbo being fed 3.0+ Liters of exhaust flow, boost threshold will be much lower than if it was a single-staged setup.
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Vacuum forming gives great detail but for your Ferrari inspiration and using thicker materials do a Google search on drape forming. Simplier shapes but you can create inexpensive wood male molds, heat your clear sheet material and drape form it over your mold to create your part.
I have to agree, if you search my posts, drape forming is what I used to do windows a long time ago. I think I even described the 'oven' I made using several heat guns and an old electric oven thermostat. Get it all evenly heated, pick it up with tongs and gingerly drape it over you buck, if you get frisky, have an oversized 'die' to lay over it that will hold it tight to the form while it cools. Then trim and start over on another piece.
I had the chance to pick up a vacuum forming setup from a friend, but wasn't interested at that time. It would have been good for parts, it was for making bubbletop skylights for vans (groovy, man!) and was about the right size for headlight covers. Though with some two-piece molds/bucks you might be able to drape it over a buck and press the B section over and make a passable headlight cover...cosmetically at least. I would still think vacuum forming would be the way to go there. Then again low pressure could work the same way to press the piece over a positive buck...pressure is only a relative thing when discussing vacuum....
Turbo Intake Plenum
in Fuel Delivery
Posted
Ohh, post five. LOL
I'm repeating myself. Argh!