Xnke
-
Posts
1985 -
Joined
-
Last visited
-
Days Won
9
Content Type
Profiles
Forums
Blogs
Events
Gallery
Downloads
Store
Posts posted by Xnke
-
-
Problem is that even a large blowoff valve for a centrifugal compressor can't dump fast enough for the positive displacement compressors, according to most manufacturers. I have a Bosch blowoff valve here; the 1" in and out kind. I will figure a way to plumb it in if the Single-Throttle intake can't do it either.
I am getting cut deep though...I really wanted the ITB manifold to work well. I did N/A...
That and my 15.5" runner length is now 13.5". Again, second choice. It will still work well, but it isn't what I originally wanted. We'll see how it goes...I got time yesterday to machine the 0.280" thick lash pads I was able to buy from Nissan down to the 0.215" that I'll need to run the new Isky cam profile.
-
Yes, I mean the one integrated into the Eaton M62. It's the same setup Magnuson uses when blowing through the throttle plates; although they don't build kits to do that, they do sell the exact same valve for this exact same purpose, plumbed in exactly the same way that I did, with the instruction to do it that way. Same with Harrop; those two just resell the Eaton product. Kenne Bell also sells a very similar unit, along with a low-vaccum model of the same unit.
It does work well, when it *works*. But 80kpa is not enough to open the valve...70kpa is though. I was getting valve flutter at idle, the valve would close on acceleration, and then flutter once cruising was sustained. Cruising MAP is right about 76kpa...which meant the valve was being buffeted open and closed rapidly, causing MAF signal instability. Converting to a vacuum-only setup cured the flutter, but caused an unsafe condition where the supercharger doesn't get bypassed if the throttle is open to a throttle angle producing a higher manifold pressure than 80-ish kpa.
It is an interesting feeling though, when you're moving from acceleration to cruise and you "feel" the blow off as well as hear the supercharger unload...
-
Unfortunately, it's become a moot point; after getting the setup to work on the MAF sensor I soon found out I had zero control of the bypass valve. The ITB system doesn't generate enough manifold vacuum to pop the valve, and more than once today I had a scary problem...the throttles were blown open. That was a deal killer...no throttle control and NO power brakes.
The manifold has been converted from 45mm ITB's to a single 65mm throttle, Final vacuum line placement will finish up tomorrow morning; and tomorrow afternoon I should have the manifold back on the car and a usable speed-density tune setup again. I will use the MAF for datalogging purposes, for now.
Right before the throttles got blown open, I was pushing 8.8lbs of boost at 3000RPM and 80*F IAT. Mass flow was 157g/second.
-
Well, the MAF sensor does NOT like the fluttering bypass valve. The bypass valve is vacuum/boost operated, and is a 2" diameter butterfly valve.
It uses a vacuum/boost actuator, with a vacuum signal on one side and a boost signal on the other side. At idle, the butterfly seems to "flutter", due to the noisy map signal from the cam plus ITB's. I should have gone with a single throttle...I'd be done tuning by now.
I have a fuel filter inline with the MAP sensor line, but my MAP signal still sucks. It's clean enough after some smoothing, but I need to fix it.
The car will cruise "OK", but as soon as you roll on the throttle and the bypass valve starts fluttering, the MAF goes nuts and the car throws a fit. All the way up to that point, though, it feels good. I don't have much option on the bypass...without one the super will start blowing pipes off on any kind of drop throttle event. I have to recirculate behind the MAF sensor in any case.
-
Well, here's the deal...ITB mode will not work with any pressure over atmospheric, because it checks baro on startup. It's hardcoded into the current system, and hasn't been changed yet.
So far, the only way to get ITB mode to run with boost is dual map sensors, with the second sensor setup for "realtime baro correction", and install the baro sensor infront of the throttles, so it sees 100kpa on startup. As "atmospheric" pressure rises it increases fueling. It's not a perfect method...more akin to using a rising rate fuel pressure regulator on a stock ECU.
Tomarrow I have to machine a new tensioner pulley and fit another brace on the tensioner bracket. Once that's done, most of the fabrication work is done, and it's just nitpicky stuff like getting the idle set correctly, tuning the pneumatic actuator for the bypass valve, and getting the MAP signal steady enough to reliably run the spark map.
The transmission is still sitting in my floor...
-
I don't have any real room to put a lot of tubing between the maf and the filter...but the filter will be going into an airbox. The MAF was bolted directly to the airbox in the original application, so I figure if that worked for a production car (most all production cars) then I could do worse than to emulate them.
More composite work will be needed to get an airbox built, but now that i am not spending three weeks on street tuning, I have a little time to get that done.
I think I'll have to pull cool air from a fenderwell...any real downsides to that? It's a low pressure, moderate turbulance area, with potential for debris, but the other option is go straight down and pull air from beside the starter.
-
I run a similar cam right now...and it's OK. Power comes in at 2800, really feels good about 3200 and pulls fine to 7000RPM and more...should make power to 8000RPM max, but my pistons won't go that high, so I set the limiter at 7100 most of the time.
-
Yeah, it's adjustable in the newest alpha code versions...and you don't want to tell it that it's a 1 bar. If you do, it won't run at all...different voltage ranges. I *DID* get it to run a little on ITB mode N/A, and it was much smoother...but...
This car is a total animal under boost. I hooked the MAF up with no filter on it this evening, it's just floating there on the inlet to the super. Slapped the needs-work belt tensioner on there and snugged up the belt, hooked up the pneumatic bypass controls, and fired it up on MAF-only fueling, with a speed-density spark map. Never made it over 2500RPM and it's already AWESOME.
Having a very good MAF curve is essential! So far, I have done ZERO adjustment to the MAF curve, and have carefully edited my AFR target table to put me at about 12.5:1 under boost, and 13.8 when out of boost for now. I'll adjust the fueling later, once I have the MAF curve fully proven. (I'll probably do most of the fueling adjustments on the dyno in late June/early July.
This is TOTALLY the way to go, if the engine is well suited to MAF operation and a good quality unit can be obtained with appropriate flow ratings. It really is a plug-and-drive operation, if you have a good curve!
Tonight, I'll be finishing up all the minor vacuum leaks (thus the tuning for rich operation right now...vacuum leaks will cause a lean condition under vacuum and a rich condition under boost) and figuring out an air filter. I would love to get a filter box made and installed so I can duct cool air to the filter, but I need a filter to go on there first! The belt will come off and the tensioner adjustments will be made, then I'll be reassembling the tensioner and hoping my belt tracking problem will be fixed.
-
Nah, it's probably ok. Just fix the drain line and it should clear the oil out in a few minutes of run time.
-
ITB mode absolutely will NOT currently work with a boosted motor. It has no idea how to handle a MAP signal over 100kpa; and the developers are not concerned with it right now...too many other things on the table. It wouldn't be too hard to get it to deal with the MAP signal properly, but as it sits now...ITB mode doesn't do boost.
(wish I'd known that when I started!)
Anyway, the MAF sensor will be mounted in the car this evening, and I'll have to work out an air filter mount. It is supposed to rain every day for the next month...just about. There are two days with a rain chance of less than 50%, so hopefully I'll get the transmission installed on those days.
-
You need a larger drain line...OEM is about 1/2" inside diameter...so minimum of -8, clear through...remember the fittings neck down inside. I'd go with a -10 drain line if you're going to use AN fittings, or just use the stock tube...it doesn't hold any kind of pressure.
Oil backing up in the drain line will kill a turbo very quickly by coking up and scoring up the rear bearing. It's the most common mode of failure in home-made turbo setups, and it's how I buy a LOT of nice turbos for very cheap....all they need is a GOOD cleaning and a rebuild and they're good as new.
I've seen a Turbonetics T3/T4 hybrid unit killed in under 3000 miles because of oil coking.
-
It'll do close to 350 grams/second of airflow, which I won't exceed with this supercharger. I would be very close to maxing out the N60 Nissan MAF, but it would fit so much better...argh.
I am going to be hunting down a 4" cone air filter and a piece of 3"-ish hose to clamp the MAF to the inlet of the super, and I'll give it a go tomarrow. Should pull about 4.5g/second of air at 1100RPM Idle, which I can datalog (after modifying the logger! Why does everyone always just assume I'll use speed-density!?!) to make sure I have the calibration curve correct, and If it's correct I'll flip the maps up and see if I can get it to drive politely on the MAF...it would be so bitchin' if it works...HUGE amount of time saved.
The list of "finish this NOW!" is below:
Make the car run and drive acceptably
Make the car run and drive under boost
Exchange transmisison and shorten driveshaft
Put the studs into the hood vent. Finished up with 3 layers of 6.5oz cloth, 2 layers of chopmat, and 3 layers of 6.5oz cloth.
Bolt the hood vent onto the already-holed hood. (did it this afternoon, It isn't so bad. I could probably just leave a hole in it if I *had* to, but I don't have to and I've already got the vent ready to bond studs into to bolt it down.
Proper MAF sizing (this one is just a little too big, but i can deal with it) means better drivability; which is going to be the hard thing to get with blended tables and ITB's with MS2-extra. Going for max power, the blended table system should be fine...but the MAF setup should give me better in-town manners for far less effort, so I hope it works out for me. If it doesn't, well I've driven a rowdy car for a bit, I can deal with it for a little longer.
-
As far as the actual tuning goes, the speed-density part of the map is going well. The alpha-N portion just doesn't have very good tools yet, and it's slow going. I've been trying to get a few hours of tuning done at a time, a little every day, and mixing in some mechanical work to keep my mind from going berserk on this. Hopefully I'll have some good shots of the hood bubble tomarrow.
-
As far as being lean and snapping out the throttles, I've got most of that cured. The timing curve is the same one I ran on this motor with the old intake; and it's only a lean snap occassionally right now. Putting your foot into the throttle sends the motor dead rich at this point; but even dead rich it is getting squirrly on the constantly wet pavement.
Lots of tuning to do. It's getting better, once I figured out the TPSdot issue I wasn't so upset with the work/result curve. I will be driving the car to work in the morning.
I did get the hood cut out and the cut edges painted this afternoon, and I'm rocking the UPS hood vent right now. (cardboard box taped onto the hood.) It's only there to keep moisture off the paint till it cures up.
-
Well, I found the big problem...there is a bug in MS2/extra v3.2.4 that really makes TpsDot flip it's wig. This, in turn, causes the accel enrichment to trigger when it shouldnt, and sends the engine into such a rich mix that it stalls...the rpms drop, accel enrichment drops, engine catches, revs up, accel kicks in, ect.
Moving to the 3.3Alpha5_gslender_v2.8 modified code changes the TPSdot system to a moving anchor type setup, backported from MS3. This cured the issue, and now I'm just tuning two tables; the Alpha-N table has to be done by hand, but the speed-density side of things is being handled pretty easy by the autotuner. It takes some time to get the tuner setup, but once it is, it handles things OK. It's not perfect, but it gets me close enough to make the adjustments by hand. It cruises a little rough, accel is ok, low-rpm, low load is crappy and I'm still working on it. The constant rain is KILLING me...I can't get on it much at all without blowing a tire off. Yes, I'm still running an open R200 diff...the OBX helical is on the list to obtain this year.
All of this may go out the window if I can get my ford MAF installed...I have a nicely calibrated curve for it and it will handle the HP with plenty of headroom. I will have to do only minor tweaking to the correction table, but it seems to be the universally preferred method for boosted ITB's in factory installations. With MS2-extra, if you have a good calibration curve it's a plug-and-drive tune. Directly metering the air coming in, plus directly metering the fuel going in, makes for very little tuning to be done...set your AFR tables and the computer is already doing the math.
Just have to figure out how to get the behemouth installed! I have a Nissan N60 MAF too, which would be easier to install between the intercooler and the manifold...but I don't have a good calibration curve for it. The ford MAF would have to go pre-super, and I'm not sure what kind of compensation I'd have to do to make up for the temperature change from the intercooler.
It's a Ford Taurus SHO V8 MAF, good for as much as 400HP. It's also the unit installed on the Ford Lightning pickup. In the lightning, it's installed as a draw-through meter right infront of an Eaton M112, so I know it can handle that type of service. The only issue I have is room! This thing is just BIG. 80mm diameter; Ford F50F-12B597-AA AF80H-01A.
Even if I don't use it for fueling, having a calibrated mass air meter would allow for ballpark HP estimates based on real airflow numbers, so it's a decent tuning aid. More air being consumed = more horsepower out, generally.
-
Ok, no improvement at ALL on this front. The car is undrivable. At this rate, I will never get it running correctly. An LS1 is really looking good right now.
I'm getting ignition hiccups at idle, and while driving the car bucks SO HARD I'm afraid of snapping an input shaft. Yes, It's that bad. My face has hit the steering wheel a few times.
Nothing at all should be causing this. There is nothing special here compared to any other ITB intake, I'm not running any boost, there is NOTHING at all wrong, mechanically. I can't find any noise electrically, but the MS resets and I hear a fuel pump relay clicking, or the RPM burps, or I get another bloodied nose from the car pitching me into the dash again. Alpha-N tuning in megasquirt REALLY sucks. There are apparently NO tools for it, everything is completely setup for MAP only setups, and even the logging tools in tunerstudio don't seem to be able to do it. I've followed all the instructions I can find anywhere on any website for any engine in any car and can't find any rhyme or reason to it.
-
Sounds like a shift fork failure. Z-ya's failure sounds like a bearing let go...lets everything go boom real quick at those power levels.
-
Made the switch to MS2-extra; and am tuning the alpha-n table right now. Car feels great from idle to about 3500 so far; as long as you are accellerating. On a cruise throttle, the car wants to go seriously lean and jerks and misfires pretty bad. Autotune wasn't even CLOSE to being able to correct this, so some gross tuning adjustments and we'll see how it goes.
-
Yep, abandoned this. Picked up an MS2-extra chip today.
-
Feels terrible. I may have been able to get control of the spark map, I'll know if it worked after work today. No plenum installed, so I am pretty much just running long-runner ITB's right now.
-
I *think* I have this fixed. I am not positive, but I Think I got it.
-
It runs!
No plenum installed, IAT sensor hanging out in the breeze, zero control over the spark map due to some code issues and snorting fire out the trumpets, but I was able to drive the car around the block a few times this evening.
It revs FAST, and it's not even close to tuned correctly! No exhaust leaks, no intake leaks, idle vacuum about 68kpa. I could probably still run speed-density on this...
-
Guess you didn't read the first post there, dexter...he is not looking for the "go turbo" response. Sometimes a turbo is NOT what you want!
-
I am converting over to hybrid alpha-n with my MS-1 Extra setup, and have made the appropriate changes to the code to setup the spark map to use Kpa instead of TPS for load. Fueling is still done based on TPS. 8 years ago, when this mod was first made, This is how it was done for the code version "HR09C". Yes, I know this is the hi-res code...that shouldn't matter at all. The mod was initially done on "H21U" codebase.
The mod needed is in red text here, and I've followed it exactly. The engine runs, but tunerstudio balks when I try to open the spark table up, saying it can't find the bins. I'm not sure where to go from here.
In msns-extra.ini:
#elif ALPHA_N
;tpsBins3 = array, U08, 156, [ 12], "TPS", 1.0, 0.0, 0.0, 255.0, 0
mapBins3 = array, U08, 156, [ 12], "kPa", 1.0, 0.0, 0.0, 255.0, 0#elif ALPHA_N
;yBins = tpsBins3, tpsADC
yBins = mapBins3, mapIn msns-extra.asm:
***************************************************************************
STTABLELOOKUP:
; First, determine if in Speed-density or Alpha-N mode. If in Alpha-N
; mode, then replace the variable "kpa" with the contents of "tps".
; This will not break anything, since this check is performed again when
; multiplying MAP against the enrichments, and the SCI version of the
; variable is MAP, not kpa
lda feature9_f
bit #MassAirFlwb
beq SD_ALPHa_N ; Are we using a MAF on pin X7?
lda o2_fpadc ; Using MAF thats on pin X7
sta kpa_n
bra ST_STEP_1
SD_ALPHa_N:
lda config13_f1 ; Check if in speed-density or
; Aplha-N mode
bit #$04 ; Use BIT instead of brset because
; outside of zero-page
beq Kpa_n_Kpa ; Branch if the bit is clear
lda kpa ; Alpha_N Mode
sta kpa_n ; Added so as KPa can be used
; elsewhere in code
bra ST_STEP_1
Kpa_n_Kpa: ; Speed Den Mode
lda kpa
sta kpa_n ; Added so as KPa can be used
Anyone got any ideas? The guys over on MS-extra forums don't seem to give a crap about it anymore, since it's "old tech, move up to MS-2 Extra".
I Will eventually upgrade...but I do not have the money to do it today.
Positively Displaced
in Turbo / Supercharger
Posted
Well, now that the intake has been converted to the single-throttle intake (not that it couldn't be converted back...) it's been sidestepped for now. Back to speed-density tuning, and weird vacuum.
Driving around today on the same runners, same plenum, but with at 65mm ford throttle body bolted to the front of the plenum, I'm cruising at 83-84kpa! WHAT THE HELL!?
Even my old twin-50mm intake manifold cruised at 72-73kpa. Hell, the ITB'S cruised at 78kpa!
There has got to be a vacuum leak somewhere. I'm still N/A at the moment, trying to get the S/C cam swapped over and broken in. Something is not right.
That, and my 70mph vibration is getting worse...I think the trans is really starting to go now. Cam goes in tomarrow night, and transmission goes in as soon as possible.