Man you guys make this sound easy! The Formato prom I bought was way off. Block learns all 108. Just loaded with fuel. I have tried the methods described on the list but am totally confused. If I chart data, I get different BLM values for the same RPM and MAP. IE at say 2000 RPM 24 MAP, I have a BLM of 128 at one data point and 138 at another. Should I take the average BLM for a group of RPM's and MAP's? Should I lock the block learn to 128 and tune by the integer?

I need some guidance here. I tapped the Formato prom (couldn't fool me!) and their method of VE tuning goes against everthing I learned so I'm convinced that I have to get out of this terrible mess myself.

TIA
JN



[This message has been edited by 89vette (edited June 26, 2001).]

 

I'd send it back and tell 'em to get it right this time.

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-Greg

'85 Trans Am - WS6,TPI:
Original owner, original paint/engine/interior, plus the usual bolt-ons

 

I'll have the new one tomorrow. I'm not expecting it to work they way I want it.

Jason

 

Its not going to work the way you want unless you do it. Hopefully they will do ALOT of chips for you but it still won't be right.

Drop me an email on how you read the chip if you wouldn't mind

Brendan

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1987 IROC-Z L98,SuperRam,EB 6085's,LPE 219/219 Roller, Crane 1.6RR, EB TPI Base, 58mm TB, ADS 24#, AFPR, K&N, EB TES, Catco Cat, 3" Borla Cat-Back, Accel cap,rotor,distro/other crap, MSD 6AL, MSD Blaster 3, Aluminum DS, 94 Disk Rear, Adjustable Valve, Precision 3.73 Gears, Sub-Frame Connectors, Hotchkis Lower Control Arms, KYB Shocks/Struts, Suspension Techniques Lowering Springs, Polyurethan Bushings all over the place, Moog Upper/Lower Ball joints and Tie Rods ends/Idler Arm,

To see the ROC, Check out the webpage Here

 

Compare that one to the oem one and split the difference and see what that gets you.
Very often it's easier to start with a stock bin., and go from there, rather then figure out what some of the aftermarket guys have done.
Raising the VE entry increases fuel.
Just note where there is too much fuel, and start dropping the numbers for roughing things out other then WOT I generally change things 10% till I go too far. This is with the aid of a scanner and reading plugs

 

Nobody likes to hear "I told ya so" ... but ...

We told ya so.

It is impossible for them to get the PROM right. Impossible. You can do it quicker yourself. One reason that you might have different points on the curve is that the car is still learning what the trim factors should be. BLMs of 108? Geeeez. Just print out that P730 fuel tuning post and read it over several times. It really does work. If you have any specific questions then post back. How much money did that formato PROM cost you?????

Eventually your BLMs at particular RPM vs MAP (kPa) will be somewhat stable. Just take that BLM divide it by 128 and then multiply the result against the VE for that RPM vs MAP. That is all you need in order to get the fuel curve close.

Example ...
BLM = 108
RPM = 800
MAP = 60kPa
Current VE = 52

108 / 128 = 0.84375
0.84375 * 52 = 43.9

Just take 43.9 and plug it into the 800RPM vs 60kPa VE cell. Do a bunch of these values and then view the GRAPH of the VE curve. The new values you entered will be rather obvious. Now begin tweaking the graph to smooth it out in order to bring the other values in line with the new values. Then burn a PROM, reset the ECM, allow the ECM to relearn, collect data, and repeat. It doesn't get any easier than that. Read the P730 post. It has more detail.

Tim

------------------
TRAXION's 1990 IROC-Z
Best Time = 12.244 @ 112.51mph (1.778 60' / 7.819@88.32mph in the 1/8)
All Natural. No Force. No Drugs. Stock Bottom End. Stock Body Panels.
Gunning for NA 11's with bigger cam, bigger stall, and bigger exhaust.
-=ICON Motorsports=-
Moderator: PROM board at thirdgen.org

 

Trax,
I read P730 about 15 times. I understand what you are doing but I seem to be chasing my tail with the different block learn values. I paid $500.00 for the Formato prom and it was out of desperation. My wife is ready to kick me and my car out of the house because I'm always workign on it! I have been screwing with this Miniram and tuning for a year now.

I'm totally frustrated beyond beleif. I have so much money in this car and I can't enjoy it. I just have to keep plugging away I guess. The more 7730 custom bins I see the more different they are. Not to beg but would it help if you took a quick scan on my bin? CAn I see some of yours before the big cam swap? I 'm interested in the general shape of your graphed VE curves with the miniram.

thanks

 

Here's $.02 worth of suggestion - the stock 92 Vette LT-1 bin was a speed-density system, and I would think the shape of those VE tables would be similar to what a MR should look like, at least for a starting point, with allowance for how your cam looks compared to an LT1.

I installed a SR on my 91 L98 about 6 months ago, and have been tuning the fuel and spark curves (off and on) ever since. The LT1 SD bin is a lot more instructive example (a better go-by) than the L98 curves were for my particular application.

I used the general LT1 shape, and moved it down and around some to match the VE of the specific engine I built. (I modeled mine first on Desktop Dyno to get an idea of general shape and magnitude of the engine's expected VE curve to start with.)

As a further note, my initial SR bins (reflecting my design model) were way rich everywhere too. I wound up correcting the fuel around the idle points first, and have been working outward and upward from there, a few points at a time. In retrospect it probably would have been smarter to drop the whole curve by a few percent until my idle points were closer, and then made corrections from there.

FWIW, I've been through around 2 dozen bin designs so far to get my fuel curves at 128 BLM for just about every VE point up to 3600 RPM. Now I'm working on the upper RPM's and the spark curves before I take it to a dyno for final WOT tuning.

HTH

DrJ

 

Mr Tim...

By doing the above as you have suggested ....will this not just result in getting rid of the long term fuel trims....you know where the integrator tries to drag the blm values back to 128/128.

I know i am new at trying to understand this but my target afr is 12.5 to 12.7 or whatever makes me the most hp. I am not trying to achieve afr of 14.7 to 1.

Or are you suggesting get to 128/128 which i equate to an afr of 14.7 to 1 AND THEN look for max power?

Mr. David

 

Its a moot point. The BLMs are locked at WOT because the car is in Open Loop. Thus, BLMs can't be used for tuning WOT ... which makes a lot of sense anyhow because the O2 sensor is not accurate at those AFRs.

All I am talking about is tuning PART THROTTLE where the target is stoichiometric 14.7:1. WOT (i.e. PE) is a different story entirely.

Tim

------------------
TRAXION's 1990 IROC-Z
Best Time = 12.244 @ 112.51mph (1.778 60' / 7.819@88.32mph in the 1/8)
All Natural. No Force. No Drugs. Stock Bottom End. Stock Body Panels.
Gunning for NA 11's with bigger cam, bigger stall, and bigger exhaust.
-=ICON Motorsports=-
Moderator: PROM board at thirdgen.org

[This message has been edited by TRAXION (edited June 27, 2001).]

 

I understand better now - thanks Tim. It does not make sense to tune part throttle any different than 14.7 unless you want to go leaner or you have other mechanical issues which shouldn't be masked by tuning anyways.

Dave

 

Quick EXAMPLE of what an upper VE table of a MiniRammed motor MIGHT look like

http://www.xecu.net/timsiford/ve.jpg

Tim

------------------
TRAXION's 1990 IROC-Z
Best Time = 12.244 @ 112.51mph (1.778 60' / 7.819@88.32mph in the 1/8)
All Natural. No Force. No Drugs. Stock Bottom End. Stock Body Panels.
Gunning for NA 11's with bigger cam, bigger stall, and bigger exhaust.
-=ICON Motorsports=-
Moderator: PROM board at thirdgen.org