I have posts on a miriad of items that I have had experience with. The majority of my TPI car ventures have been MAF cars, and the majority of my speed density experience has been with TBI. I need to know real world first person experiences about how much I am going to be able to get away with on my '92 with cam and intake. Everyone that sells chips swears you cant even put a K&N on them without a custom $$$chip$$$. we all know this is not true. I know from working with the TBI SD vehicles that a significant amount of leeway in displacement, intake, and non-compu camshaft can be tolerated before the problem gets so serious that an adjustable FPR cant fix the problem. I know that the TPI fuel vs. vacuum maps are not that far off from the TBI ones for the SD vehicles. My question therefore is how much. Please no regurgitated magazine tripe. we get enough of that around here. I would like to hear about any experimentation others have done on the SD tpi cars, like 305 to 350 or 305-350 to way larger swaps, cams; like way wrong grinds that still functioned, or intakes that you were told would not work without a chip but did any ways. please share with me any info you have. about the parts, and how the vehicles response, driveability, and power reacted.

 

B4CTom1,
You'll probably have more luck asking on the Prom forum. Power Adder board is for nitrous/forced induction. The MAP systems aren't that sensitive that it won't run, but otherwise the engine won't know that it's ingesting more air with your cam/heads. I moved this topic to the Prom board. You can get a prom writer setup for under $200, get some dyno time with a wide-band O2, and be all set. Good luck.

Andris
Z28tt-89 IROC T56 DFI Twin Turbo, with speed density DFI

 

It sounds to me like you are looking for the "easy" answer - modifying the engine without having to reprogram the eprom. Yes, you can actually make a number of modifications to SD TPI that don't need an eprom change to "just run". But will the eprom be optimal? Far from it. In fact, the stock eprom on a stock engine is far from optimal due to GM's own design. I personally find SD TPI tends to be overly rich.

The biggest reason people tend to modify the eprom is because they have altered the VE of the engine and it needs to have the fuel tables altered. Heads, cam and intake is going to require a completely new set of fuel tables because where the engine requires fuel is going to be different at various load/rpm ranges than the stock eprom. Further, if you change the injector size (because you are now making more HP and need more fuel), you are going to have to tell the ECM about this, or it is not going to be able to give the proper amount of fuel.

If you had a car with a carb and non-computer controlled distributor, would you run the stock setup (including jets and rods) if you have modified the cam, heads and intake? Of course not, you are going to have to at least re-jet the carb. So why do you think that you would not do the same with the ECM?

Frankly, even bone stock MAF cars can benefit from a "tuned" eprom. And that is what eprom burning is all about - "tuning" your engine. It just is done differently than with an old-fashioned carb/dissy, but many of the "concepts" are still the same: get the optimal fuel mixture and spark advance at various RPM/Load to get the maximum HP your engine is capable of producing.

I strongly encourage you to consider to learn how to burn your own eproms. This will result in the BEST eprom for engine as only you will spend the time "tuning, tweaking and testing" that is needed to get the max from your motor.

Start by reading Traxion's Prom Burning Article to learn what equipment and software you need. You can get into eprom burning surprisingly cheap, depending how much of a "do-it-yourselfer" you are.

With the proper eprom, you can run camshaft durations that you wouldn't think possible. And when it comes to the "wild setups", SD is actually better than MAF. Though I have also found that you can run some pretty awesome setups on MAF too.

 

I understand. But here is a question that only a prom guy might be able to answer, how come we can build 500-900 RWHP daily driver MAF cars that have perfect A/F on our dyno with the stock computer and and have enough stock timing that we have to retard it only by about a degree or so at high RPM and how would a custom prom help there? Is speed density that different? Also when I have gone up in injector size on MAF or SD cars the BL and Int. have compensated for the change without a prom? I have come here for help and I think that answers to Questions like these will help me dispell any misunderstandings, and show my need to custom progam and what I will have to change when I begin custom chipping a car. instead of building proms, we have wideband O2 dyno tune the FMU to get a perfect A/F ratio. We have actually had to remove several "major tuner" custom calibrated chips, computers and modules (I'm not talking about ADS, hypertech, or superchips either) on fords and chevys to produce the power the customer should have in the first place on their "extra aspirated" cars because our A/F monitor says the fuel curver were un-Ideal. Dont get me wrong I have had some expirience with aftermarket ECMs like speedpro, holley (C-950), older accel. but I only like to use those as a last resort, mostly because of expense, but also because I cant stop myself from fiddling with them every minute at the track. None of my peers have to do this, they are kicking back and kicking *** with stock ECM's It is in my experience (not just opinion) that if you can get a car to run and drive with good power and performance on a stock ECM, adjusting no more than the FPR and base timing. that later when a blower is added the remainder of the tuning can be done with mostly the FMU and the dyno. That is why I must know if the car will run ok with say a solid roller with about 110-111 degrees lobe sep, very mild overlap, medium sized duration, and a ton of lift. It should still generate a decent amount of vacuum for the map, but add that to a car with a different intake manifold and I wonder if I'm going to get it to start, idle, have some semblance of throttle response without dying every time I come to a stop before the blower even? If I have to I will, but isnt the perpose of using EFI over carbs for the simplicity? I do want to know what you have to say, straighten me out, put me on the right path, this is hard for me because usually I'm the shell answer man, I guess we all have our limitations. thank you in advance.

 

Gotta pic of this 3rd Gen FBod with 900 RWHP, daily Driver?.

 

I with Bruce on this one. Some timeslips would be nice. I've played with both and I have pushed MAF systems probably further than most guys. But when you start approaching 500 HP at the crank (400HP RW), MAF starts to show some serious limitations EVEN when you are burning your own eprom.

MAF cars need to have their eprom "kludged" once you max the MAF @ 255 gm/sec. The "kludge" invoives using the adding more fuel with the PE AF Ratio vs RPM table. Without this modification to the table, there is no stinking way a MAF will run properly and you seriously risk running lean.

Both SD and MAF have a problem in terms of the max HP they can produce just by the fact of the type of injectors they use. Unfortunately it is NO WHERE NEAR 900 RWHP. EVen 900 Crank HP would require "high impedence" injectors of close to 60# @ 100% DC.

See what you can learn when you get into eprom burning?

 

if there is a fudge in my statement its not the 500-900 hp part it is the kinds of cars. I work on lots of GM cars here, blown and otherwise, but because of the "nickel and dime me" nature of my GM cohorts they do not often acheive the kind of power of the fords I am forced to build daily. pie in the sky cars with giant budgets, but my tuning methods have been the SAME on the GM's and the fords! this is a poor picture because this car stands on the bumper sometimes, the classes of the NMRA and others do not allow wheelie bars, how stupid! this car was the #11 qualifier at the PSCA race at phoenix in october. if you live in the front range metro area of the rockies you know this car from the king street races. I thought you might like it better than a dyno sheet because HP is nothing if you cant put it down (with 10.5" even) I want my 3rd gen to stomp this cars *** in the dirt (see signature)

 

I knew you guys would help set me straight on the burning, but even if the car is ready in a month I need to spend years learning prom burning to build proms?

 

Yep a real street car.
yawn.
When you want to get back to reality, feel free to post.
Chest beating means about 0 with me.
And my friends car can run X.0s for ETs

On the subject of MAFs, I have the capability to read 510 gms/sec. Which puts me in the *fun* league. (An interesting exercise is running the math about what HP that 510 will support).

For the higher HP levels MAP is the way to go.
If for no other reason then to get rid of the MAFs restriction.

In an earlier comment you mentioned FMU, I fail to see where that will make much of a difference on a N/A engine. If you/them are running Boosted and running with in a degree of the oem cal., then you are way off (MO), so again your story isn't adding up.

Do you have a specific question after all this?.

 

Actually, the mechanics of learning to burn eprom is FAR SIMPLER than that. I've had guys "pop over" and taught them the "mechanics" of eprom burning in a few hours...it is that simple.

The part that takes awhile is the "tuning" aspect. Most guys have never had to learn how to "tune" an engine and that is generally what takes the longest time. In my opinion, if a person has a good understanding on how to "tune" an engine, then once they overcome the initial "learning curve" of how to burn the eprom, they generally can learn how to burn a GOOD eprom fairly quickly.

FYI, most of the guys on this Board (excluding people like Grumpy who I consider the Board's guru) got into eprom burning only in the last year. In fact, I think only about a handful have been burning eproms more than a year. Most have been only doing it for 3-6 months. That's how easy it is.

If you can turn an engine, then you will have no problem getting into eprom burning. It's far simpler than you think. This is why so many of us who DO burn our own eproms are so admitant on why buying an eprom is a waste of money.

Go here --> https://www.thirdgen.org/newdesign/tech/promintro.shtml to find out what you need and how to get started.

 

it belonged to a customer who sold it to my business partner here at www.outlawperformance.com after we built it and he was too scared to race it, so now Don drives it every day except in snow or when the engine is on the dyno (like now), it is titled, plated, and insured in the state of wyoming and driven as far as 130 miles to bandemere (denver, CO) or douglas (WY) for track or street races. We built it from the ground up, literally there is not one single bolt or bit of wire we did not remove during its race-steration from "cop car" to "cops like it car". It has an NHRA certified 6.5 chromoly cage to subframe but uses stock suspension location, layout, and geometry which makes zipping around town lots of fun. the dumbest thing on the car is the dzused on hood. the fasteners have bitten the $6000 paint job around the engine bay and this detracks otherwise from its perfection. I hate working on mustangs, but it pays the bills. it also has full interior but the radio doesnt work or the A/C but the heater does (it gets cold streetracing sometimes). but it along with the interior, and suspension, and stock wheel wells; they are all required by the sanctioning bodies for the races he attends (and I watch the shop alone). And if you want to know what it turned (time slip) then pick up a copy of RACE PAGES or FASTEST STREET CAR and look at the PSCA standings for the #11 qualifier from the phonix race referred to earlier. All I want is to beat him and still be as streetable as he. see signature. I want to be the #1 qualifier someday at an NFRA race.

 

I noticed that there is a winbin and a gme program "dos based" will win bin work on older dinasaur computers with say windows 3.1 or is that too old? it is a nice little subnotebook I have that could finally find use in its retirement years. it is in good shape with a good battery but it is only like 25 or 50 Mhz. I was just afraid that my DOS skills are too wasted (suck) to operate the GME bin handler. what do you think of this little laptop idea. I know that these are small files (bins) thats why I ask.

 

If you havent clicked on/read my signature I take it you didnt know about the ATI F-1 (I'm a procharger dealer among others), we work mostly on and build from scratch supercharged and turbocharged vehicles here and I intend on using an F-1 in my car with a 3 core intercooler to avoid the hacking required with vortech YS trim and d-1RX trim 3rd gens. that is what the FMU mention was about. the reason it may seem that I am speaking of a N/A engine is because if you can get the engine tuned and running before you put the blower on then you can get the rest dialed in within 1 hp of the fanciest chip under full boost. but if it wont run, drive, idle, and perform when N/A (thats what I need a chip for) then it is moot. the reason I say 1 hp is because if the dyno says the A/F is perfect (ideal) through the whole run and the engine wont take anymore timing without detonating through out the entire range of the run, how would a chip help? It would help by allowing me to drive it to the shop for the dyno in the first place, or get it on the dyno, or drive it home, or as a base for which to work the FMU and aftermarket CD ignition base timing off of. If I happen to find a way (using a higher bar MAP) to make this all happen then I might get rid of the old tried and true ways for some new ones. like prom burning. you guys have opened my eyes to the fact that hte car will not have any driveability (even though skulte said it would) and given me a way to get that larger injectors I wanted without the hit and miss of using the stock BLX and int. part of my computer. I am about to get (buy) another 3rd gen a 91 for test perposes that could help me a bunch https://www.thirdgen.org/rides/index...ew&rideid=8293 it seems that what is needed is to form little partnerships with guys that have similar setups to share findings and info, I think my dyno could be invaluble in that kind of situation, is that the way it is normally done? I will look into the equipment but I need to know about that old laptop I got (see above post). I'm actually a nice guy willing to bend over backwards for customers and aquantances alike. I'm not just here to cry for help and talk crap, and act like I never needed your help in the first place, because I do need your help.

 

For "boost" applications where you want the ECM to control for "au naturel" but the FMU for "boost", MAP seems to be an easier way to go.

With MAF, you get fuel correction to 255. Thus the difficulty is when to have the FMU take over to add addition fuel since you can have a "boost" situation with MAF still ready < 255 (at low rpms) and you can have "naturel" when the MAF is maxing.

With MAP, the triggering of the FMU is far simpler. If the MAP sensor < 100 Kpa, you run off the eprom. > 100 Kpa, use the FMU to augment the fuel.

I've know a few guys that have tried running a SC without any FMU and purely off the eprom and not using an ECM/eprom designed for "boost" application (like '749). The '730 MAP guys find it easier to tune an eprom that works reasonably well than the '165 MAF guys.

As for an old DOS notebook, sure that will work for most of that. I personally prefer an older Notebook with W/95 because it allows me to use the Pocket Programmer's Windows Based software (much nicer than the older DOS based FILEPROM) and also TunerCat (which is Windows based).

My W95 notebook I was able to pick up at Flea Market for $25.00. The battery is dead and won't hold a charge (that's okay I run an DC/AC Power Invertor off my cig lighter to power the charger), and I had to reformat the HD and reload W95 (I had the OS laying around from an old desktop that died years ago).

 

right on, I saw what grumpy was talking about with the MAP and I was always curious if there were enough adaptable values to allow a guy to use a different bar map to run an S/C application without the FMU ( like factory ). I have fiddled with the older accel DFI (and a few others) and the fuel tables and changes were serious business. I was able to get the car very close on the dyno but I often believed that there was something more I could have done if I had a more definitive grasp of the "ins and outs" of that system. I also hear that system is very similar to the system (uses the same motorola controller) we have in our cars. are there guys that have addapted other applications (other cars) ECM's and parts (GM) to the TPI cars. like later sequential and larger MAF systems? I think I will just use what Ive got for now.

 

Tom,

for the bin tweaking and prom burning I use my desktop machine (I have to boot into Win95. ugh ). The only time I use my laptop is for the ALDL interfacing.

You're posting on the net so you must have a fast computer somewhere right?

 

yeah our over taxed showroom computer, and the dyno computer that we run win 95 on, but its peripherals are full of dyno wiring. but that wont stop me, a trip to ebay may be required, as well as new IBM old stock 166 mhz laptops were email spamming me from ebay so I saved it in my filing cabnet, if you are interested in seeing it I can forward it to you.