BOTTLEDZ28

iTrader: (9)

Im considering doing a full exhaust upgrade on my 91 Z28 350 with Dyno Don headers and ypipe (no cats) and a Magnaflow catback. Only other "upgrades" would be filters and gutting the air filter housing out. Besides those changes, the car is stock minus the suspension changes.

Can the exhaust upgrade be done and not have to get involved with custom proms? I do not have the time to get into DIY Prom burning and I dont know who can do mail order Proms for these mods that actually work.

Will the stock ECM compensate for the exhaust upgrade and tweak the tables in the tune so that the car still continues to run correctly?

Orr89RocZ

iTrader: (20)

It will be fine

BOTTLEDZ28

iTrader: (9)

Thank you. I dont want to get too deep into this car. Its a low mileage car in near perfect condition. Its weekend only cruiser too.

AmorgetRS

iTrader: (6)

Another it will be fine. Did SLP headers, gutted cat, and a Hooker catback on my 91 Formula and did nothing to the computer.

Thirdgen89GTA

iTrader: (5)

Bolt-ons alone are not enough to throw the ECM off its game.

Cam or heads though, and that gets different.

no new tires

Leave the battery un-plugged for awhile. Then start it and drive around for awhile. This engages the "learn".

Vanilla Ice

As would skipping this process altogether.

no new tires

You do what you want -

Vanilla Ice

The car will run just fine, but will be nowhere near optimal.

I can walk you through tuning yourself in a matter of minutes for the basics.
Really you'll be touching less than 5 tables. It isn't rocket science, it's easier than installing your exhaust.

I wrote the getting started tuning the OBD1 LT1 howto. I'm thinking this community needs one with simple vocabulary and easy explanations.

Way too many people are afraid to tune (or even get tuned!) and are making these cars slower than they should be.

BOTTLEDZ28

iTrader: (9)

I don't even know the first thing about tuning or what kind of equipment I would even need to buy. The exhaust is the only thing I plan on doing to this car unless an SLP T Ram falls into my lap. Been there, done that on my last car. It ends up turning into a full time job that is in the garage, broke, more than its out on the road being enjoyed.

Vanilla Ice

i can give you the direct links to exactly what you need.
3 purchases. About $150 total.

Technically you could skip $60 of it if you ship a prom to somebody to burn it for you. I'll do it for $20 to cover return shipping and the time to take it to drop off to ship.

I don't care. Just saying, free help and learn to tune what you need for now, by yourself in a few minutes.

BOTTLEDZ28

iTrader: (9)

What's stopping me from buying a used prom on eBay, that plugs into my 7730 and then just have someone overwrite the entire tune with the same tune that my car has now and then tweak it?
Now, I would have my OEM prom that hasn't been messed with just in case I want to return the car to stock

Vanilla Ice

Couple reasons.

You'll still need to buy everything else.
What you're buying makes it all reversible to stock already.

Vanilla Ice

http://www.moates.net/gp1-package-gm....html?cPath=64
This gives you a very easy way to put in a new prom... And gives you two proms for swapping. Then all you do is take it off if you want to go back to stock.

https://www.amazon.com/gp/aw/d/B00K7...?ie=UTF8&psc=1
This is the burner for the two proms you get in the package above.

http://www.aldlcable.com/products/aldlobd1u.asp
This is the cable to datalog.

This is the exact setup I have. I use a netbook for all the software needed. All free.

After this you download tunerpro rt v5, the aujp bin (found through a link on this site), aujp Xdf, aujp ads. The last two are on the tunerpro website.

If I must I can link to all of that too.

Vanilla Ice

That's it. That's your setup. Get it up and running and it's simple from there too. All you'd play with is timing and only basic fueling.

BOTTLEDZ28

iTrader: (9)

Ok so for roughly $178, I can burn custom proms that have altered tables from the stock tune? For a stock car with just an exhaust upgrade what kind of benefits am I looking at here? I would hate to spend the money AND devote a ton of my time to reading up on what I need to do only to get maybe 5 more hp out of the car over a stock tune.

I will never ever ever do heads and cam. This is a 50K mile car that I don't want to turn into a racecar. I just want a better sounding exhaust on it but I also don't want to slowly ruin the engine because the more free flowing exhaust has caused the engine to run less than optimal.

BOTTLEDZ28

iTrader: (9)

And Im sure it will be more than $178. I need a way to see if the changes made are doing anything.

Vanilla Ice

No that includes a way to datalog. That's the aldl cable.

As far as gains I would imagine that you should feel the power increase. And if you get really into it you can get MPG to increase too. Then a wideband and do your fueling and get even more power.

No sweat off my sack if you don't, this info is now here for anybody in the future.

BOTTLEDZ28

iTrader: (9)

well, I greatly appreciate all the info you have provided me here. I guess I will have to give it some thought and figure out what I want to do. This is at the most a 3000 mile per year car so I'll have to see if venturing into the prom burning is worth my time and effort.

If there was a proven tune that worked for any 90-92 350 TPI car that just had exhaust work done then I would gladly just send my computer out to someone who could reflash it. Just not sure how perfect those mail order tunes are.

Vanilla Ice

Honestly if that's all it's for its a waste of time. Unless you like car projects that don't require you to get dirty.

It will make the car more future proof should your plans change. And it will increase power and as you get more comfortable it opens up many options like the saujp rom.

I got into it because i hated mail order tunes, and it's a free power bonus every single time you upgrade after.

edpontiac91

iTrader: (2)

If SLP could make a 50 hp package for our 3rd Gens AND name the company of what SLP stands for and that is STREET LEGAL PERFORMANCE. Just adding the Headers/ Performance exhaust system and a set of Intake Runners will make 5200 rpm seem like a no sweat in every gear, compared with it running out of breath now around 4600 rpm. You will not suffer ANY difference in the idle or gas mileage (except when you stick your foot into it more often). Lets also do one more thing and install a MSD-6AL and Coil and notice after that your exhaust pipe has almost ZERO black carbon residue inside of it. That tells me all the fuel is being brunt. I know from experience because I have been running the above system (plus a little more) for over 20 years with my 1991 Formula 350 showcar. You could also go with an upgraded Prom Chip and let them know what mods you have made and allow for more performance without any hassle. Little things like a 160* thermostat helps-using a 5W30W oil like Royal Purple or Mobil 1-K & N air filter etc. You get the picture, don't be afraid your car is going to blow up, now just go out enjoy the benefits of BOLT-ON performance. High Performance Pontiac did a 6 page article on my Bird, to show just how much improvement could be made with ONLY BOLT-ON parts, such as SLP, Edlebrock, Hypertech, Hotchkis, Alston and more!

toronto formula

iTrader: (1)

vanilla ice is this an open offer to help?
I would love to tune but the perceived cost and difficulty stopped me ?
Is it really that simple to tune?

Bottled sorry for interrupting your thread

1991_RS

I might be contacting you down the road!

NufNuffZ28

iTrader: (10)

IMO at this point I am with the you will be OK network.


You will get no SES with your mods, and you can use timing and FP changes to tune it in at WOT.

The stock ECM is plenty fat on these cars stock. I tuned a buddies HSR car and we still had to take fuel out on the top end. (2/10 easy gain with less fuel in the tune). Then bumped timing slightly and it picked up more. Would only back it down when we sprayed.

If you plan on going more later, it's not a bad idea to start learning how to tune now, so when those bigger mods come you're already tuning.

1MeanZ

iTrader: (9)

I've been tuning these cars for 10years now and I'm much closer if you want local help. Shoot me a PM where in Western MI you are located.

For just an exhaust I wouldn't bother with learning to tune unless you are also going to install and use a Wideband O2 sensor. The stock calibration with only an exhaust added simply won't be off that far. Without good O2 data, you've got a 50/50 chance of making the tune worse rather than better. Without O2 data, all you can really do is dial the ignition timing up till you get knock and then back it off 1-2 degrees.

Contrary to popular belief, there isn't that much power hiding in TPI cars because they don't have an overly conservative factory calibration like the TBI cars do.

Vanilla Ice

I can feel a considerable amount to be gained with fixing the stock tune. Without even looking at a datalog. Power isn't the only reason to tune it.

1MeanZ

iTrader: (9)

How many of these cars have you tuned?

Tuning without even looking at a datalog? I assume you're only referring to adjusting ignition timing?

Of course power isn't the only reason to tune, if you're talking about fan temps, VATS delete, EGR/AIR delete, etc. But I'm sure with only an exhaust his BLMs won't be so far out that you'll get better drivability due to better fueling.

Since my definition of "better" might be different than everyone else's here is an example. 92RS(real slow) has an '89 IROC with a L98/A4/2.77 gear. He has Dyno Don headers and a GMMG cat back, car is otherwise stock. It has 17x9.5 rims and 275 tires all around. On the stock tune if you went WOT from a dead stop if might squeal the tires a little bit, but it was pretty much hooked. After I got done, it would spin the tires hard enough from a dead stop that it would slide sideways a little bit until it got going enough to start to hook. Once rolling, the car felt stronger, but it's not like it was a totally different car. Yes it was noticeably better, yes it was worth the effort, but I wouldn't say it was a huge gain either.

BOTTLEDZ28

iTrader: (9)

Vanilla and/or 1meanZ, I dont want to alter my oem prom so if I bought a prom on ebay, could you flash it with the stock oem tune in my car now and then tweak it from there so I could just swap the proms out without having down time on the car?

I got a code 32 today for an EGR and I plan on removing the AIR system. I have heard the GM had a TSB on these cars for the code 32 and basically installed new Proms with a slightly different tune in them to stop the false code 32.

I want to just get rid of the EGR, AIR, VATS, and then tweak the tune a bit. Can you make this happen on you time and my dime?

1MeanZ

iTrader: (9)

PM sent

Vanilla Ice

I was specifically speaking of driveability tuning. I have tuned both timing and fueling and many other things by feel with no datalog. You can completely tune a car without a datalog.

1MeanZ

iTrader: (9)

I'm speechless......

Vanilla Ice

They did it before computers. Not saying it's equal or better but a datalog is not necessary.

ploegi

Think about what you are saying there.... Tuning a computer controlled car, without a computer? That doesn't sound very plausible to me......

That said, sure, you can tweak a tune without data logs, however, you can get it dialed in a LOT more accurately with one......

Vanilla Ice

I thought I made it clear with the "not saying it's equal or better" part?

It would take substantially longer but it's possible to dial in pretty good, but not great by any means.

ploegi

Musta missed that part.

Data logging just makes the job a LOT easier..... If you have the car to hand, and the equipment to do tuning, you also have the equipment to do data logging.

FormulasOnly

Just a heads up I got the TunerProRT and Moates cable. It took a while to figure out how to set it up just to data log. The set up is not intuitive at all and theres not a whole lot of written instruction I could find on how to set it up and run it. Youtube was a big help. That being said you've got to remember you're talking to a computer designed in the early 80's and the fact that TunerPro and Moates have made it possible is impressive.
Just don't go into it thinking its like a modern day OBDII plug and play tuner.

SKFengineer

I'm with ForulasOnly. I have an '87 IROC I bought the Moates Cable and the TunerPro with the plan of datalogging and the computer would NEVER talk with with the laptop. I received lots of help from people here on TGO and GearHead EFI and everyone came to the same conclusion the '87 ECM can be tough to deal with... I don't want to talk too badly of what can be a very rewarding experience but it's not just about the money, these are old computers from the time of Atari and PacMan, really amazing for the time but there is no promise this will work out of the box without tweaks.

To the OP the general thought is if you bolt something to the motor or change something attached to the motor you are fairly safe with the stock tune. If you dive into the motor: fuel injector size, heads, cam, displacement changes you will need to make ECM changes. There are always exceptions and the chance that you could leave a percentage of performance on the table but changing the exhaust is a no-brainer and you'll be fine. I've been thinking about the exhaust setup you outlined in the first post and I'd love to hear how it sounds when your done. Right now I have Edlebrock TES headers into a 3 inch exhaust ending with a flowmaster muffler. It's loud and people tell me it sounds good but I'm getting tired of the cambered exhaust sound and I've heard MagnaFlow and Dyno-Max have better flowbench results. (Don't read me wrong I still love loud pipes just want to change the type of sound they make. )

Vanilla Ice

It's not a chance, it's a certainty.

It took me an hour to get my cable working due to multiple tuning platforms requiring drivers caused a headache. But it worked flawlessly once done.

I don't understand the hate on obd1 and prom burning. To me it's better than flash tuning. I had a headache just this week flashing a tune to a GTP where it lost enough batt voltage it auto quit and compromised the data and we lost communication. Had to buy a new PCM. Doesn't happen with PROM burning.

Thirdgen89GTA

iTrader: (5)

on the other side of that, flashing a PCM shouldn't take so long as to have voltage drop.

I've never had an issue flashing my LT1 pcm.

Thirdgen89GTA

iTrader: (5)

You can't tune an EFI car without seeing what the computer is doing.

Vanilla Ice

I never had that problem with my cars either. This is just one example of a flash going wrong. The cause is irrelevant, it's the effect. The PCM is "bricked" and needs repair.

Yes, you can.

Thirdgen89GTA

iTrader: (5)

If you can program a Prom, that means you have access to a computer, and likely a laptop in this day and age. So you should just use a datalog program and get the real data so you can really look at it and make changes based on hard data.

Vanilla Ice

We already covered the logistics of that topic. Read the whole thread so we don't have to repeat anything else.

Thirdgen89GTA

iTrader: (5)

The only person tuning without datalogs is you, singular. Its like hammering nails in with your fist because using a hammer is too difficult.

Vanilla Ice

Thanks so much Bill for your input. The point was made a week ago and was pulled out of context then. It has since been resolved, yet you still want to talk about it.

If you'd like to continue we can chat about any old irrelevant topics you'd like in PM. I won't address this here again.