ill def get a wideband for it...i don't screw around when it might cost me my motor..

i just wish i had a better understanding of this ecm and eprom and all that jazz... it looks like im going to need 3 different things to be able to tune the thing

 

I'm not convinced that all you need is a wide band 02 sensor for tuning. That said, will it help? Absolutely. Will you be able to max everything out without a dyno? Not sure you can.

Is there a best AFR for every vehicle or is there a generally good AFR and you tweak it from there? If it is the former, no problem. If it is the latter, how will you achieve it without a dyno?

 

Timeslips!

 

Here's a pic of the Greenwood scoop I was thinking of...
http://forums.corvetteforum.com/1577576043-post77.html

BTW,,,With an ALDL connection and TunerPro (or TunerCat), you monitor BLM/INT values to adjust MAF tables for partial throttle openings. It's pretty easy. When you get those right, factory-like percentage enrichment for warm-up should also be close. Observation works best to dial open-loop operation after that.

WOT is the challenge. The ECM goes open loop when the pedal is mashed. WOT fueling is presented exactly as stored (w/o adjustment by the ECM to hit stoich mixture). Start by adding 15% fuel for open loop. I varied mine by the inherent VE of my (TPI) intake. At each rpm (interval), I increased fuel by the percentage increase in rpms -- while also adjusting for any increase/decrease in VE. Came out pretty close.

WOT operation is where a dyno or WB provides the best feedback since you can target a specific (or the best ET) AFR. Dyno/trap times can certainly help fine-tune for best power.

Look at the DIY Prom section in ThirdGen.org for the best ODB1 educational primers.

 

Haven't posted here in quite a while, but I have a lil' experience in what u want.

1st, u are either very young or very old. I say that because it sounds like u have alot of dreams for ur car and haven't really thought out the costs. Or, ur old school in thinking that, as in the 70's, one could make a minor intake, header change and go from a 14 sec to a low 13 sec ride, depending on the car/engine, w/ relatively little bucks. It ain't gonna happen with these models of Corvettes!

I have done most of what everyone here has already advised u to do, including the "Greenwood scoop"

My advice to you, is to look seriously at your priorities and end goals. If it's just to get a 12 sec car, sell ur C4 and get u a C5, C6 or another car that is close from the factory. U'll be alot happier and lots of money ahead in the long run. If it's to improve the performance of ur C4 and it just has to be this particular car, assess ur goals and needs/wants.

A 300 hp TPI is not only possible but easily obtainable and will be "relatively" cheap. (Relative being the operative word, here ). I highly recommend reading Lingenfelter's book on TPI motors. It not only has been done, but has been done by many people using several different combos. I can tell u that NO intake alone will get u to 300 rwhp. It's the total package. What all of these people have told u so far, is going to be alot of money that u have "invested" on a car u will never get a monetary return out of. Consider it the cost of admission or the cost of having fun and money that is just.... GONE!

My advice to u is to leave ur car stock, and enjoy it for what it is. Is it 2011 technology with over 400 hp? No it isn't. It's an 80's/90's machine that performed very well when it was new, in that age of that technology. Nowadays, it's a good looker with average or below average performance, compared to similar cars. In the end, u'll be happier and still have money in ur pocket to enjoy other things. If u do decide to throw money onto the car, be prepared for a big loss when u eventually sell, and, in the end u will STILL only have a car that will perform average, compared to say a newer C6, Camaro, Mustang, etc. From experience, Tom.

 

No, not necessarily. However what i can tell you is that even with some of the best "dyno tuners" out there whats the most amount they're going to spend on your car? a few hours maybe? and sure thats plenty of time to get yourself a damn good running machine but it will never be perfect. Perfect or at least very close to it IMHO takes dozens upon dozens of end user adjustment by a knowledgeable owner to get every little aspect just how they want it.

Am i saying I'm good enough to do this right now? No. But i will say that im willing to learn beyond what i know at this point and the only way to do that is to get your hands dirty

thanks for the info, my car doesnt have a MAF (91) not sure if its a speed density type program or MAP.. anyways im looking forward to getting inside this ecm and seeing how things go down

Well, I'm not fresh outta high school but i'm not exactly elderly either at he ripe old age of 23


I know it sounds like i have no idea whats going on and ive never been down this road before but in fact i have... I already own a mid 12 second daily driver and trust me it took tons of work countless hours on my back and more then i care to speculate on in front of a laptop getting the tune dialed in along with assloads of money to get it to where it is now. its just gotten to the point where its quite well setup and ts time to move on to project #2..this vette.

I see where you're coming from with the buy another better stock vehicle plan and i agree..however to me thats not as fun/interesting..plus this vette has some sentimental value to me.

Video of my truck. her quickest to date is 12.44 but i don't have that one on video http://www.youtube.com/watch?v=RtkgL...eature=related

 

now that thats said another random question... Taken manifold restrictions out of the equation.. what kind of number can guys put down with stock non-ported heads?

 

Lets not forget that they also have tons of experience, assuming they are doing it for a living and good at it. So your their 1 hour might be the equivalent of you spending several hours at it. Obviously if you go to Joe's Bar and Grill and Tuning Service, sure but when they have been doing this for years, I'd say they can spend several hours and get it as close as it can be done if they use a dyno, AFR, etc, etc and all the tools.

Therein lies the rub. You don't get knowledgeable by reading a book and then start tuning. It takes years of experience. Also, it will take several "oops" items to know how far you push it. It isn't going to be as simple as buying an FSM and tearing out your heads. This means that in the meantime, your car isn't going to be all it can be. Me personally, I can't wait. I want it running as good as it gets NOW and not in several years. After all, if you want to be a "weekend warrior" and be as good, you will take a longer time.

Neither do I but to me, mastering such a skill for 1 car isn't really worth it. OTOH, if I am fielding a race team and we are making daily tweaks, yes. One car which needs a fix every few years? Where is the economy. I had my car dyno tuned and until I do something radical like new heads, cam or blower, I am not sure how often I will use that skill

 

you would be surprised how often you will make changes to your tuning when your able to do it whenever you want and for free...

i got all the same arguments with my truck..blah blah it wont be fast/you'll blow it up and all that jazz when the fact of the matter is tuning isn't rocket science. Not taking ANYTHING away from those who are good at it as its very hard to master and takes a lot of work but as long as you're sensible and have a head on your shoulders you should not overly worry about causing damage... are there "opps"? yes..they usually result in a less drivable car or a worse time slip however thinking that everyone has a catastrophic engine melting mistake along the learning road is silly.

My plan would be this,.. own the software/hardware to be able to tune myself...save my stock tune then have the base tune done by a professional and tweak it from there. Its worked well for me before and that truck is in the top 15 trucks in the country still on a stock turbo/fuel sysetm

 

It did cross my mind when my friend was at the Ford dealership that had a dyno and could sneak me in for a couple of beers but if I had to pay for a dyno session every now and then to make tweaks, all I have to say is this. It had best be some serious tweaks that will generate something quantifiable for the money I spend. Without the dyno, I am not sure how I would verify what I just did vs what I gained.

Having helped in blowing up a friend's motor during the learning process, I guess I tend to assume the worst and see if we can tolerate that mess before I go into it again. Not sure why but we double checked the values but somehow got a number transposed and nobody caught it till we did a post mortem.

Can I ask what more you managed to squeeze out of it? Professional tune vs your tweaks?

 

well i never made a pass on the exact tune i got from the professional... after i got it on the street i was a little unhappy with the fueling values and specially the egt's...i pulled a little fuel out of it and first pass went 12.60... since then with little tweaks and things to the tune and general setup of the car its been down to 12.44@108.

If i had run it was the exact tune i got it still would of only went 12.60 tops seeing as even after i puled some fuel out it was still a little overfueled and it managed to maintain better fuel rail pressure after i took the max pulse down a little over 100us.

the real gains in my case came from better boost control and more exact timing..it took A LOT of playing with but im happy with the result


and you don't have to be on a dyno to make changes...being at the track is a good way to see what helps along with the good old butt dyno. also, a lot of tuning is about general drive ability and mileage etc etc dyno's wont help you with this

 

BTW, how do you guys feel about these? price seems a little too good to be true but hey never know

http://www.summitracing.com/parts/HED-68440/

 

If an amateur like you can tune it that much, no offense to you, I am thinking your tuner has left way too much on the table. 0.16 gain is huge. I saw Lingenfeter when he was tuning my car. He put in a wide band sensor and other probing stuff and took readings and made adjustments till it started to go south then he brought it back to the peak. So did Brian Ebert at HiTech Motorsport. I am wondering if your tuner didn't do that and just wrote the tune, made a couple of runs and declared he was happy.

 

no he did a good job the thing is dyno's and the steet/strip aren't the same. specially on turbo cars like mine its a different type of loading and there's more resistance on the vehicle. along with just the feel of daily driving which I changed a lot. Remember when a tuner tunes he makes it to have it should feel perfect in his mind... only you can make it perfect for yourself.

also not all of that .16 was tuning i made some chassis changes as well

 

mini ram, cam, tune, catback

If the d36 will hold up.......

 

thats a reasonable number to expect on stock heads with a cam?


Edit: looked it up and the d36 is the diff right?

im a little more concerned with my stock clutch

 

FWIW, I just finished my build and had it dyno tuned yesterday... 91 L98 with Ported plenum, SLP runners, TPiS Bigmouth manifold, Comp Cam CC502, Hedman Headers, Corsa cat back, open air box. Everything else (heads, injectors, main cat, bottom end) all bone stock. Best pull was 338hp at about 4900 rpm. I think torque maxed out at 376lbs.
The guys at Big Daddy Performance in Lakewood did the tune. They were great to work with.

 

but for the money spent on the slp runners, the bigmouth, and ported plenum wouldn't it be not much more to just get the miniram? and better in the end?

mniram can be had for what 900?

BTW how did the headman's go for you? i like them but im a little afraid of the price...

oh and lakewood NJ or NY?

 

www.firstfuelinjection.com $850-$900 gets the intake and TB. This is what Z01#316 is running on his vette (pic in collage a few posts up).

If you get the Hedman's, pick the Elite series if you've got the money. More people satisfied with that line though both have been used. I'd choose based on how long you'll keep the car....a couple of years or longer.

 

well other then the paint coming off and them rusting i believe even the cheap ones comes with a lifetime warranty against cracking or breakage.

im just a cheap bastard deep down but i dont wanna get something that will cause me too much grief