I just had to get in on this one :-) I have met johnny(and troy the sales rep?) in person twice in the last 3 yrs (various races etc) and i will admit as far as magazines go gmhtp is the shizit...Where else does anyone here find regular installments of thirdgen related tech, let alone buick turbo buildups? Theres no hot rod tv sensation of coming back after a commercial break and look our 8000hp 672 donovan big block with a 6-71 is installed and already on the chasis dyno :-) It breaks u hear about it, prices run over and/or under budget they tell u...what they test and the results they get, they also tell u......... How many other magazines out there that u know of have fragged as much stuff as these guys have in one fashion or another? they nuked a 3.8T , destroyed the rear in their birdie and i know there are quite a few others that have had their day as well................they do one thing well and that is tell it like it is in the real world....... Unlike most here(notice i didnt say all, and u know who u are) i actually work on cars for a living and 90% of the conversations on these boards comes from people who in reality dont even have remotely close to the clue that they think they do when it comes to their vehicles as far as power output and tuning it goes(truth hurts)... As far as people go who say yeah but u still broke it, guess what? if u havent broken anything than your not doing something right it all breaks eventually and believe me it even happens to people who work on vehicles for a living (trust me i know ask me about my formula) And while yes i will stick up for gmhtp as a whole the project magnum tpi has been a hell of a let down, considering it was to start out as a tpi buildup(read project car one or two mods at a time).... So yeah the 4000$ shortblock alone made me want to grab my ankles (im puttin that much total into my 3.8T in the TTA). But it is his car, not the magazines or anyone elses and the statement of being smog legal was made from day one and if u have roller dyno smog tests then u build the car to pass it .....but i still dont think anyone whos shopping for a nice tpi car is going to be dumping a 396 into it(at least most of them arent). But anyone who says u need to run a dfi to get the full beneift of that setup is ludicrous :-) Last time i checked u yourself johnny were running a Turbo-T well into the 11's on that lil'ole pathetic P6 ecm(which quite a few cars have run into the 10's and a few 9's but i have not seen the 9's personally) in there, now werent u :-) The 730 ECM u could easily swap into magnum is a quite bit more advanced than the p6 cuold ever dream of being..... I do believe that DFI and SpeedPro/FAST have their place but i do not believe they are necessary unless your going for balls to the walls limit or in need of running low impedance injectors(inj. driver changes in ecm have a spotty history).. And as far as the new Accel DFI begin the shizit, did u ever notice that they are now playing catchup to SpeedPro/FAST? heres another one for u since your so gung-ho on the wide band 02 setup(which believe me i love and would step up to aftermarket ecm funds permitting(wide open throttle o2 control is sweet for those who have seen it in action)) is that the SpeedPro/FAST and Accel DFI use the same o2 and the price difference is about 250$ if u say u have an Accel DFI vs. a SpeedPro/Fast setup.. u know more than enuff people to make the phonecalls and find out for yourself, or come spend some time at a chicago land buick GSCA chapter meeting . In the self prom burning vs. aftermarker ecm vs. aftermarket chip debate i can promise all who read this one thing. If u call in your specs to someone who will make u a custom chip do not, i repeat do not expect it to be remotely accurate as a whole :-) I have been there done that and seen a few other from acquaintances as well.. usually within a day or two i can have it diling and better part throttle driveability than a 200-400$ custom chip ever will(the good ones at least work with u, scan data/chip revisions/etc, but these all require u to send the chip back to them for reprogramming meaning more down time for your ride) I will also admit i am far from perfect when it comes to tuning and learning by leaps and bounds almost every major revision i make.. Its not that it takes alot of time(learning does until u understand what is happening), its that u have to understand the theory behind it.. With an aftermarket ecm the theory isnt as critical u have more leeway when being able to do live instataneous changes and have wideband 02's for feedback, but this costs u 2k$.. doing it yourself requires some time investment to figure it out a slow old laptop for logging and some type of definition file editor for your specific car, whihc ends up running u from 200$ to 1000$ depending on whic specific setups u use..but it can be done very cheaply... Like i said in the beginning i respect gmhtp and the people that work for it, but that doesnt mean i think they always do the right thing or are the word of ***, but it all comes down to whose car it is and what their vision of it is.......And if u read this dont take offense, i live at this site almost every nite for at least 2 hrs after i turn wrenches at work for 8+ hrs a day and usually come home and work on my own vehicles and/or friends cars for another 2-3 hrs a nite.. I have been there and done that and gotten my hands on quite a few toys and have seen some amazing stuff whether it was homemade or bought with a lot of $$$$$$$$... I've also broke destroyed and mangled cars and embarrasses myself with pathetic track times after a round of mods went wrong :-) I miss anything anyone else wants me to comment on? I will. Its about having fun not roasting each other :-P later Jeremy Centanni PS #1 Johnny piss off some advertisers and do a write up or two on PROM burning (you've mentioned it in your mag enuff but only in captions) #2 I talked to u long ago of doing the background info stories on the TTA and the SY/Ty like u did for the turbo regals, ever gonna happen? My two cents and very liberal thoughts :-)

After spending a few sessions with Kevin Crain doing some PROM burning and seeing the high level of committment he has to it, I came to the conclusion early on that I did not have the time or energy to put the necessary effort into buying the equipment and learning the process. At any rate, Kevin is quite good, but even he could not get a satisfactory result on any of the occasions we tried. Besides Kevin, both Steve Cole (TTS) and Ed Wright gave it a shot.

Time is money, and since it takes so long to "get it right" with a stock computer, I've concluded that a DFI is actually cheaper, especially if I'm going to try different combos in the ensuing years.

To Johnny Hunkins -

When you guys do a feature on a car, do the pics have to be taken by you guys or can the owner send them in? And if the owner can send them in, do you guys prefer digital pics or actual photo paper pics, or negatives? If GMHTP has to take the pics, would the owner have to take the car to you or would GMHTP go to the owner's state/city to do the photo-shoot?

I have a 1991 Z-28 that I have completely restored inside and out and have been told by many that it is magazine quality. It has taken me 3 years so far to restore the car and the project is near completion. (I'm still waiting for my back-ordered SDPC Vortec TPI intake to arrive). Is there anyway that I can send you a pic for you to determine if the car is good enough to grace the pages of GMHTP?

Please let me know and thank you for your consideration!

I will post time slips on this board as soon as I have a few hundred miles on the new motor!

Mike (1bad91Z)

I don't know who kevin crain is, or what methods he used and showed to you, so I probably already look like an idiot here but I just had to comment. DIY PROM burning is what you make of it. It does take a bit of time to learn the technology and lingo and whatnot, but once you are over that hurtle, it really is quite easy and fast. And with software like VEmaster to make it even easier (it intreprets the ALDL data stream and corrects your VE tables), AFR modifier, and of course tunercat, it really is a nearly painless process once you get over the initial bump. After that, it's all tuning - and whether you're tuning a holley carb and fully mechanical distributor, or an aftermarket DFI or factory ECM, it's all about timing and fuel. And if it is so much easier, why did you still have the work outsourced?

I just re-read the jan 03 project magnum article and here is some additional comments about it.

I'm not sure how the software is generating the VE maps from the screen shot you show in the mag, because nowhere on that screen does it take into account the things that really affect the VE table (intake, heads, exhaust). I will also say that tuning the VE table on the 90-92 '730 ECM is anything BUT trial and error, let alone dismal. There is very exacting and simple methods behind it.

Why does it seem like you are actually down on the GM ecm here? I don't know of anyone here who has GM's powertrain department at our disposal, but we all seem to manage. And i'm not talking about myself here (yes my car is slow and yes I burnt the chip for it and yes the stock heads and cam and intake and exhaust manifolds are on it, that's why it's slow). I'm talking about the other folks who are also deep into the 12's on the factory ECM who have proved that it IS possible and practical to do it with 12 year old electronics, and without the help of GM's powertrain dept.

The thing I just don't understand, is that most of the things said about the DFI, my stock computer just does fine, thank you. There is mention of the IAC control, and of increasing the IAC steps when the AC is on, and what not. Yup - factory computers' got this, and it can be tuned with just a few keystrokes. Spark advance table, VE table, my stock computer has both of those too. And I can tune and edit them in a windows enviroment too.

I will grant you that the ability to run the UEGO and use peak&hold injectors is quite nice, along with that target AFR table (you can still set target WOT AFR on GM's '730 ECM, but in a slightly roundabout way).

I guess more than anything else, is I'd like to see GMHTP at least be knowledgeable about the factory systems before they get downed in the magazine. Misleading, inaccurate and ill-informed statements such as "because to make max power in a street engine like our 396, it's just not practical, or even possible, with 14-year old electronics" just doesn't help anyone out. To those who know better, it makes it obvious that there was a serious lack of knowledge of the factory system in the first place. It sounds, to me, just as bad as "because to be successful in bracket racing, it's just not practical, or even possible, to run a manual transmission."

Personally, I think with you being involved with GM High Tech Performance, you owe it to yourself - and the mag - to give it a shot. It will be worth it! You can get all the equipment you need (presuming you already have a laptop) for under $350. Maybe you could make it a long term winter project to mess with for an hour every saturday, I don't know. But once you've done it and look back, you'll probably wonder why you waited this long and why you thought it would be so difficult. It really isn't. And you'll be much more informed and aware of the true abilities and limitations of the factory ECM, leading to more accurate publications and better overall quality of the mag.

10-4.

That would be a pretty damn good tech article! Trax's is very good too on this site. There should be something in print showing the possibilities out there besides going out and buying a DFI system. Another good thought.

just to be clear on this one. I don't harbor any ill feelings for you or the magazine. i might have came across as if I was taking issue with you (I'm not). i think it's cool that you are trying new things on your personal car, and even cooler that you check in with websites like these to let us know what's going on and get input.

anyhow, no hard feelings. just trying to put in my (more than) two cents in what I want to see in the mag as a paying subscriber. I hope that you do get project magnum into the 11's regardless of what computer is running it (just don't slap on a carb!! ). Regardless of computer setup, it's always nice to know what hardware works and what doesnt, and it's obvious that aftermarket fuel injection has come a LONG way since the early holley analog systems of only a few years ago.

Maybe when you are done, you can go back and explore the problems you ran into with the MAF system. There are a ton of people out there with MAF cars, and seeing some info in print on how to work with these cars (and what the real world limitations area) would be great, and very on target with the GMHTP audience.

so, like i said, no hard feelings.

Articles like the tech article I wrote on PROM programming (http://www.thirdgen.org/newdesign/tech/promintro.shtml) are what the rearders of GMHTP need to see or, at the very least, know about. I sent an e-mail to Johnny on 9/23/2000 with a link to my PROM article and how important this is in our community. No interest. I suspect that it will still be ignored even though it's a cheap way to tune your car that can produce excellent results.

FWIW - I know Kevin C. personally ... he is a good tuner and a great guy. Problem here is that Kev wasn't tuning Magnum TPI on a dyno with a Wide Band O2. You can't compare apples to apples unless you do similar things. DFI with a wide-band will easily yield more horsepower than the stock GM ECM with best guesswork. There is no substitute for Wide Band tuning.

I still can't believe you popped this question off again. If only I had a stock thirdgen with some cash to throw at it. It's times like this that I wish I would have left my car back in its previous form just so that I could give you another 'example' that you are looking for. But, as previously said, I am past that and moving in another direction. What I did - I did years ago. A stock thirdgen with the 350 can run low 12's on a large tube runner setup. It's been done too many times to count. Unless low 12's with a naturally aspirated 350 isn't fast? You don't see too many here because this setup takes some big cash to pull off and a lot of the people on this site are young and don't have the cash. This can be done with a simple AFR190 combo running a 218 cam (like the HOT cam or the CC XE 218/224 or the LPE219), fully upgraded LTR setup, 3000 stall PI Vigilante, SLP 1-3/4" headers, 58mm TB, 24lb SVO Injectors, 3" catback, high-flow dual cats, 1.6 rollers, cold air, some suspension tuning for the launch, some BFG DRs, and - most importantly - TUNING!

That's why Magnum TPI should be in the 11's. It has a 396 with a SuperRam.

I'm done. This topic has officially been beat to death.

Tim

Yup. The off-the-shelf ADS Superchip was pretty darn close as we found out, adding spark advance only ran up knock counts and the WOT fueling was as on-the-money as you'd get without a wideband O2 sensor. The old engine still had factory dish-top pistons and was doing good to hit very low 13's with long tube runner TPI induction.

The new engine, on the other hand, looks to be a runner. Low 12's are just the beginning. I suspect some more tweaking on the DFI will chip away at the ET some, and replacing that SuperRam with a hogged-out MiniRam will put it well into 11sec territory.

And 91L98Z28 you're right, ya kinda look like a 'tard. Magnum was a MAF car before this engine swap (as evidenced by the repeated mentions of the now-defunct MAF sensor) so VE tuning wasn't on the plan.

Eh, I know the car was MAF, just like all the other 85-89 TPI cars. And I know the '165's don't do VE because they aren't SD systems. I was simply commenting on the magazine article and it's description of how the DFI system makes it so easy to tune the VE table. My point was that it looks the same as VE editing in tunercat. yes, $8d has upper and lower VE tables, instead of one large table, i know. but same/same. My gripe was with how the article tended to be, ah, confusing to someone trying to understand why the factory computer was holding the power back (other than that it is old). My gut instinct is that you guys were running up against the 255g/s MAF limit, but without seeing the dyno UEGO data who knows. I do remember that some guys in the DIY PROM board here have found ways around the problem. I just would have liked to seen a little more effort invested in factory hardware that all the "little guys" can relate to and associate with (and if necessary, 165->730 conversion) instead of dropping $2000 and calling it good to go. A '730 is $20 out of the junkyard, with a little repinning and work the '730 basically has all the features of the $2000 DFI (minus wide band O2 and peak&hold drivers and whatnot) for a lot less and the end performance potential after tuning is about equal. The $1900 savings could be put into other areas to make the car quicker or more reliable.

And yes, I know I came across awful harsh. not intentional, and I've already clarified my position, and I hope that JH understands that none of this is meant personally. I want to see a fast project magnum and a great GMHTP as much as everyone else, and was just offering input.

I've personally seen an 88 formula in our car club running the STOCK MAF computer and chip. Using a set of 30lb injectors so it is no where near in tune A/F wise. SLP headers(not longtubes) that runs.
~11.7's
Doesn't qualify, but I think it shows how damn adapatable the stock ecm is. Imagine if the chip was tuned for 30lb'ers.
Oh for $2700 I am sure we can throw a couple cats and a smog pump on
My point is about the ecm not the the other parts though.

<QUOTE><B>
__________________
12.9@116mph/gtech
Got traction?

</QUOTE></B>

GTech times in sig...what's next, Desktop Dyno data for engine hp? I think this is the kind of lameness Hunkins is referring to.

My dragstrip 13.4sec car runs a GTech 12.3sec on hills. Ooooh aaaahhh...I have a 12sec car now!!

Ah yea...

Oh yea. I have a new signature ....

Tim


__________________
DD2000 numbers:
531hp @ 6500rpms
492tq @ 4500rpms

GTECH Pro numbers:
11.6@119mph

Real World figures:
Nothing. The car isn't running.

Wow you guys are stupid. I was talking about someone elses car with track times so i fail to see how it has anything to do with mine.
Second would you rather me say yeah my car feels like an 11 second car or would you believe gtech times more accurately. Sorry I can't get to a track and it's better then nothing. I know it's SO unvbelievable that a 383 can go 12.9.

It has to do w/ your sig being lame, posting artificial performance numbers is not "better than nothing."

Take it for what it's worth. It's not like I try to pass them off as track times. If you don't like it who cares.

I think what you guys are not understanding is this is the FIRST time the Magnum TPI car has ever run in its current config. And that was thru the stock MAF sensor and intake plumbing, because they didnt have anything else to try. We all know how restrictive the stock MAF sensor is, so cut Mr. Hunkins some slack.
Heck, even my own car was stuck in the 13.20's @ 106-107 MPH for over a year, before I finally popped off the 12.80 @ 108.50 in my sig. And yes its emissions legal for California. If I ever get the 60' down to something respectable, I should be in the mid to low 12's too. Oh, and by the way, my dad's shop is about a mile from your offices in Anaheim, CA.

Mr. Hunkins, you said you were going to the track again on Thursday. Was that Halloween, the 31st? How did the car run with the better intake?

First issue, I think, is to define what is and what isnt smog legal. It varies from state to state, and I see (from my standpoint) things being overlooked or neglected that in a million years would never fly here if someone looked. Define that first, then argue about whats legal and whats not. I've passed our strict test here with no EGR or AIR, so its not like passing the sniffer is a major issue IMO. The car would never pass a visual inspection. Speaking of... I do know from previous experience that some techs who are on a power trip do look at visible casting numbers, ie: the block. Bring a car in with a nice lope to it, and expect to be asked for a EO# for that cam. I'd say in the last 4-5 years its gotten less strict in that respect, but I have heard instances of people being hassled still today. So, line out what is ok and what is not, and then you can argue about who is legal and who isnt. I could throw an EGR on my intake, and unless someone did a function check, they'd never know it doesnt work.

The PROM thing.
First, is it smog legal or not? I've never heard of a tech getting in there and checking code, so I think most, if not all, of us who are doing reprogramming can get away with doing as we please in there. I carefully took off the sticker on the stockEPROM, so that I could put it on an EEPROM, and anybody anal enough to actually look wouldnt see anything funny. The check engine light still works fine. The ID on a scanner is whatever I want it to be. Nobody without programming knowledge will be the wiser. I think thats right along the line of picking a cam of your choice, who has the ability and will take the time to physically check the cam thats in the car? So basically, you pick whatever cam you want to, and as long as the car isnt shaking violently, the tech wont know.

Second, its not hard to reprogram a prom. Take the DFI or FAST as an example of aftermarket if you wish. The main difference, IMO, is having to take out the stock chip and reburn it with different code. The rest is simple, just like swapping out a carb, changing a torque converter, or the like. With the DFI and FAST, you have the same things to adjust for tuning the car, from MAP readings to spark curves, and idle parameters. There is nothing fancy about what GM did with either the MAF or SD ecm's, and all the basic things you need to change are right there. In order to reprogram, I think the best route would be the one I am mostly on now, but not quite done with yet:
1. Get a burner of your choice. The Pocket Programmer is nice because of its hookup to the computer. I have a different burner, and the only real problem with it is that I cant hook it up to my laptop. I want to be able to do that, so I can burn chips at the track.
2. Order a program to make changes to the chip. Tunercat is the most popular, and its easy to use. IMHO its no different than the DFI or FAST, its just a user interface to let you easily see and change the parameters on the chip. Just so happens, you get to use the stock ecm rather than buying something aftermarket. No rewiring required.
3. Order some EEPROM's. This will make life easy, all you have to do is stick the chip in the burner and reprogram it, rather than dealing with the whole UV light erase deal.
4. Order a new chip for the car from the dealer. Use this to change stuff, keep the original as a backup. Do not modify the original in any way, its a backup in case something goes wrong.
5. Get a second chip, new or used doesnt matter. All you need is the lower plastic piece.
6. Take the new chip, desolder the EPROM. Ok, so you dont have to do this with a DFI or FAST. But then again, I'm not rewiring either.
7. Solder in the EEPROM. If soldering is a problem, or seems difficult to you... well I dont know what to say. I've been soldering stuff since I was 6 or 7, its not hard to do. Carefully peel off the sticker from the new EPROM you got from the dealer, and stick it on the EEPROM. Now its stock
8. Stick the new chip you desoldered into the burner, get the BIN file off of it.
9. Modify the BIN file as you wish.
10. Make a tool. I will post a pic of this later. Basically, you take the stock plastic carrier, take all the chips off of it (more desoldering), and put pins in it in appropriate places. With this tool, all I do is stick it in the chip carrier with the EEPROM, and stick that in the burner. I never again have to touch the EEPROM or take the blue plastic cover off the top. It couldnt be any simpler.
11. Burn your new modified BIN file to the chip.
12. Install the new chip into the ECM, and you are done.

In the future, after you get everything ready, there are less steps to reburn. Its pretty easy to do.

I know that with a DFI or FAST, you dont have to disconnect power, pull a chip, burn it, and then reinstall and reconnect power (which I must admit does suck at times), but its still the factory ecm. Any technician can hook up to my car and see whats going on. Its smog legal. Unless I am mistaken, I dont think the DFI or FAST is 50 state legal. Please feel free to correct me if I am wrong.

Anyways, thats my .02

Here's a pic of it, I know its lousy but I think you can sorta get the idea. I thought I had a better picture, but I cant find one. Gotta love Polaroids...

Anyway:

Oh yea, and before anyone asks or emails me, not interested in making any for anyone. I think the pins were a buck or two, and the carrier was a freebie. I really dont have the time to sit here and make a part that is worth about $5, and spend an hour or two doing it. Not really worthwhile. I can give you more details and pics (I thought for sure I took a bunch, have to look again) and you can go from there.

Well put Madmax, trax, ect.

I think that Johnny being So high and Mighty on the emissions point is pretty funny.

Why Don't you Go and tell that NJ state inspection facility that you Have got a 4" Stroke Crank In that Block ?

Then tell them you have an aftermarket DFI controlling fuel and spark.

I'd like to see how "Emissions legal" and "to the letter of the law" That Would be.

I know in California They wouldnt touch that car with a 10 foot pole.

Im sure that the Car Can and will be fast, But at what Cost ? A 396" SBC w/ all those Go-fast Goodies Should Fly. Right now your Bumper to Bumper with an 03 Cobra, or 02 Zo6, fresh off the showroom Floor.

12.3 Is a pretty blah time as far as magazine project cars Go.

You Want proof of 11 second or comperable TPI cars, Well Buckyeroc, Trax, Willie, Mike Davis, Tim Burgess, and others are all there, and they have stuck it to you. Why Do you keep Dodging them ?

When the average Joe like Me Buys a Mag like GMHTP, I think "Cool, They have the same car as me, I bet I can learn something from this that will help me on My Car "

The Second I see you Guys slap on an aftermarket DFI that cost more than My Car itself, all intrest goes out the window.

Thats about as useful to Us as a Hot Rod-esque 900 hp bigblock swap Into our Cars. You Might as well buy a BMW built V-12 out of a Mclaren and Swap it in.

Yeah, Lots of power and its cool... But It dosent really do me any Good. I can't apply any of that to my own car, and as a result, Im not buying the magazine. If I wanted to read and stare and say "ooooh Ahhhhh" I would Buy Hotrod.

Johnny, The people here ARE your customers. They are telling you what you could do to Sell more magazines... So Why arent you listening ?

A detailed Article outlining PROM burning, and Its benifits and limitations, using knowledgeable referances ( Tim and Bruce, just for starters ) Would be someting even I would buy.


Hell, Stick it to Accel and Take that DFI off, let Tim spend a Day on the Dyno w/ a '730 ECM and Make the Same, Or More, Power. That would really be in the Spirit Of Your Mag, the Hobby, and this site.

Or You can just Keep Playing the battle of the checkbooks, and Watch your reader Base stray farther and farther away.

If your gonna do that, You should Probrably give up on the thirdgen and stick to 4thgens and C5's.

[quote]Originally posted by Bort62

When the average Joe like Me Buys a Mag like GMHTP, I think "Cool, They have the same car as me, I bet I can learn something from this that will help me on My Car "

The Second I see you Guys slap on an aftermarket DFI that cost more than My Car itself, all intrest goes out the window.

Thats about as useful to Us as a Hot Rod-esque 900 hp bigblock swap Into our Cars. You Might as well buy a BMW built V-12 out of a Mclaren and Swap it in.

Yeah, Lots of power and its cool... But It dosent really do me any Good. I can't apply any of that to my own car, and as a result, Im not buying the magazine. If I wanted to read and stare and say "ooooh Ahhhhh" I would Buy Hotrod.

Johnny, The people here ARE your customers. They are telling you what you could do to Sell more magazines... So Why arent you listening ?

A detailed Article outlining PROM burning, and Its benifits and limitations, using knowledgeable referances ( Tim and Bruce, just for starters ) Would be someting even I would buy.


Hell, Stick it to Accel and Take that DFI off, let Tim spend a Day on the Dyno w/ a '730 ECM and Make the Same, Or More, Power. That would really be in the Spirit Of Your Mag, the Hobby, and this site.

Or You can just Keep Playing the battle of the checkbooks, and Watch your reader Base stray farther and farther away.

If your gonna do that, You should Probrably give up on the thirdgen and stick to 4thgens and C5's. [/QUOTE

These are my thoughts exactly.....now if I could only type them that well and have them make sense.

Interesting subject.... I think the obvious question is:

Is a TPI 396 motor with a Superram, hyd roller cam, aftermarket ported aluminum heads, shorty headers, smog pump, and cat in place making 354 rwhp respectable ?

Or the other question,

Is a TPI 396 motor with a Superram, hyd roller cam, aftermarket ported aluminum heads, shorty headers, smog pump and cat in place running 12.3 @ 109 mph respectable ?

Two very different questions.

I think a TPI motor that is truly smog legal making 350+ rwhp & 400 rwtq is very, very good.

I have the 383 C4 Corvette linked to earlier in this thread, and I can tell you, I would not be making 350 + rwhp if I was truly California smog legal. Based upon my experience, even though companies such as Random makes excellent aftermarket catalytic converters, and are a definite improvement over the stock catalytic converter, they are still very big power robbers, especially on a heavily modified big cubic inch motor. I probably currently make 370 rwhp.... with a single cat, I would probably be back at around 350 rwhp, if I add the smog pump, back down to 340 rwhp, if I replaced my long tube headers, with shorties, probably back down to 325 rwhp..... I don't even want to think what the stock exhaust manifolds would do to power, but probably back down to around 300 rwhp...... my big 3" dual exhaust did not help my et's in anyway, so going back down to a 2.5" or so pipe would probably not hurt my power significantly.

His 12.3 @ 109 mph is simply a function of the heavy weight of his 3rd gen, and maybe bad air in the middle of the summer.... ? Don't know for sure. I have the GMHTP magazine somewhere here, probably should have re-read it before posting.

I will say, the aftermarket computer is not necessary to make good power...you can run it up over 400 rwhp with a functional MAF in place with a stock ecm and well matched eprom. (As a note, on the Corvetteforum, we have a member running 11.1's @ 122 mph with 406 Superram motor utilizing a solid roller cam of all things.... he's doing this with 24lb injectors, stock ecm with a Formato EPROM, and the MAF on his 85 corvette)


This is my opinion anyway... take it for whats its worth.

cheers,
Todd

Johnny - Please look at my car on my sight. The car ran an 11.80@115 right after installation and tuning of the 383. I ran with street tires and catalytic converters. Further tuning with the HR cam netted 11.71@116 with a HR cam.

I emissions tested this car in Illinois. They use the IM-240 test where they run the car on a treadmill. If you really want documentation as far as ET's and emissions inspection, email me the address to send it to.

I understand what you are saying about the way you built your car. I built mine by using my own judgement and hot rodding logic as I am on the north side of 40 years old.

By the way, the car now sports a solid roller cam 240/240@.050
.614/.614 lift and it idles better than it did with the smaller 230/236 HR cam?

www.geocities.com/dzperf

HiTech5, just wanted to echo your comment on solid roller cams. I have a 232/240 solid roller (0.525"/0.543") in the 406 in my 71 camaro. It's developing over 17" of vacuum now after about 10 miles, and I'm sure the rings are not even fully sealed up / broken in yet. It's amazing what they can do with a solid roller - I never thought a 232/240 would idle this clean (down to 600rpm no problem!) and pull so much vacuum.

Fact: GM Racing chose to use the DFI Gen 7 ECM on their 4-cylinder Ecotech-based drag cars that just finished their first year of competition in the NHRA Sport Compact series.

Question: Why might they have chosen the DFI box over their current stock ECM?

I am not trying to hype the DFI box, nor speak negatively about the stock computers. Rather, I would like to hear from you guys, some of whom are experts in calibrating with older stock computers, as to why GM Racing would chose an aftermarket computer over their own current stock piece.

My probably biased guesses:

(1) GM has DEEP pocket books
(2) the R&D guys may have had a deadline to meet in bringing out the drag car, and they may have found it faster to simply gut the car of it's entire electronics systems and just install DFI.
(3) They may have outsourced much of the work to a DFI shop. As far as I know, there isn't many "shops" that tune factory GM computers, the factory computer tuning is more of a DIY type thing, as there is no money in it (no $2000 computer to sell).
(4) the car doesn't need to be street driven or even have good street manners, so the loss of emissions systems controls are of no concern.

Certainly GM has the necessary expertise and computers to do it in-house: they have had turbo'd 4cyls before (sunbird I believE?) and everyone knows about the syclone and typhoon and even the 3800SC.

The aftermarket SC they sell for these cars, probably comes with recalibration stuff for the factory computer, as they would of course have to maintain emissions compliance and retain a computer that can do it all

I am going to rise this from the dead. This was a very interesting conversation. I didn't start getting GMHTP until a year ago. What had come of any of this? Anything new since the last posts?

IIRC the car broke into the very high 11s. Then the car was sold for a very reasonable price. I think under $11K. I have not heard much of it since.

Cool... just wondering since I read through the entire thing last night

I do not know what exactly the car ran or what it sold for, so....my info is very helpful!! lol Anyway, the asking price was not all that bad. Considering that a lot of the parts most likely were discounted for the magazine use, even though it was an employee's car. That would be my guess.

Too bad that car wasn't built with the right parts. The cam was way too weenie for that setup. About 20 more degrees dur. would have probably put that car at low 11's and add about 7mph. More compression would have helped too. I think some people get concerned and caught up in the term "streetable" way too much. That car would have had similar street manners with a lot bigger cam, since it was using EFI. These guys that don't live in CA etc. who are always whining about being emmissions legal crack me up.