mtx28

im seriously considering selling my 74 camaro this fall and getting a clean 91 or 92 Z-28. i've had an 83, as you can see from my sig, but obviously no experience with TPI setups. also, i've never messed too much with computer controlled cars. so, my question is, at what point of modification do you need to change the (computer) chip.. and doing things like changing the cam, heads, and exhaust; do these have adverse effects on the computer? or does it recognize them as 'upgrades' so to speak and operate accordingly? in case this isnt very clear, to put it simply: at what points in modifying an engine do you need to worry about the computer and change it accordingly?

------------------

• 83 Z28--ttops, 200k miles--very ragged out. sold, thank goodness
• 74 Z28--slightly modded 383, TH400 tranny, not too quick but fun to drive

IROCZTWENTYGR8

iTrader: (1)

MAF cars(85-89)do the changes for u, Speed Density(90-92)need u to do it for them. When u do bigger mods(heads, cam,....)a car will benefit from a custom chip like a FastChip because it is made to work with your mods unlike the stock chip which isn't.

------------------
Looking For:

87 IROC-Z28 350 TPI
The car I want.

84 TRANS AM 305 H.O.
Another car that would be OK to own while I still look for the IROC-Z!!

[This message has been edited by IROCZTWENTYGR8 (edited March 28, 2001).]

Kevin Irving

That's not true. First of all, you are saying that the stock PROM for a MAF car adjusts to all your mods?? Hell no. There is a point where you get to certain mods and either an aftermarket chip has to be installed or a custom PROM must be burned. If what you were saying was true NO ONE with an 85-89 TPI would need to burn a chip. Fact is the stock chips are dogs, and everyone knows it. The only shred of truth that can be gleaned from your post is the fact that a MAF system is more TOLERANT to mods, and even that is debatable.

------------------
Kevin Irving
85 Trans Am WS-6, 305 TPI, custom burned '86 PROM with '87 "165"ECM, Accel Supercoil & 8.8 Wires, MSD 6AL, Aluminum Driveshaft, Wonderbar, TB Coolant Bypass, Ported Plenum, Modified MAF, Syclone Fuel Pump, JET Airfoil

15.556 @ 86.65mph, Nov 10, 2000.... I know it sucks.. but it will get better!

http://www.geocities.com/transam85tpi/

Member - The Tidewater Trans Am Club, Norfolk VA URL=http://www.geocities.com/ttacva/]http://www.geocities.com/ttacva/[/URL]

IROCZTWENTYGR8

iTrader: (1)

Correct.

Thats what I was trying to make without writing alot about this, but I should have. The MAF is better for mods, especially for some1 that doesn't want to mess with a PROM every time they do a mod, no matter how big it is, there are some that are OK with it though. When u get into heads and cam with the MAF, that is about the time u should go with a custom chip, because before that its not really that needed on a MAF since it can make the changes needed by itself until those bigger mods are in and the stock PROM won't be good enough anymore.

------------------
Looking For:

87 IROC-Z28 350 TPI
The car I want.

84 TRANS AM 305 H.O.
Another car that would be OK to own while I still look for the IROC-Z!!



[This message has been edited by IROCZTWENTYGR8 (edited March 28, 2001).]

mtx28

so do you get error codes when the current chip can no longer deal with the new mods, or does the performance gain you expect just not happen?

Grim Reaper

Actually, burning your own eprom if far easier than people would like you to think. At that level, we Speed Density guys have a far easier time than the MAF people. The SD ecm is far more hac'd and the SD system if faster reacting.

The changes made to the SD's Volumetric Efficiency tables bare a direct relationship to the BLM/INT values. With MAF you have to do it indirectly via the MAF Scalar tables.

Take a visit to DIY PROM board and scope out some of the various posts. Also, take a look at Traxion's article on "Learning to burn your own PROM" at the top of the DIY PROM board. Just click on the link and it will give you an excellent idea as to what you need to do to burn your own eproms. It really is far easier than most people think it is.

Lastly, learning to burn your own eprom is best started when you engine is still fairly stock. This way you really can't screw up too much. You will find regardless of whether it is MAF or SD, that GM designed these eproms to be on the rich side. For optimal performance, most people find that they have to lean it out a bit on most fairly stock engines.

The biggest mistake most people make when they decide to get into eprom burning, is to wait until they modified their engine. This is not the time to begin to learn eprom burning, as you won't have a good base point to start learning with. It will be hard to see the effects of your changes to the eprom as you probably will be quite far off.

Lastly, the biggest difficulty the MAF guys are finding is the "maxing out" of the 255 gm/sec on the MAF. This can occur when you start modding your engine pretty extensively, or when you stroke it to 383; let alone putting a power adder on.

Excluding a power adder, you just have to modify the VE tables and the "displacement" of the engine on SD cars. Power adders are also a problem for SD cars as the eprom is designed to only handle a 1 bar MAP sensor. But I have been looking at the code, and I don't think it will be too difficult to incorporate a 2 bar MAP for an SD car and make it work, if you chose to go the power adder route.

Grim Reaper

I should add, that by invoking "Highway Mode" on your eprom, you can easily pay for all the equipment to burn your own eprom just from the gas you will save.

CanadianBeast

If you have the choice definatley go for the SD, If you've been to the prom board you'll see how much info there is out there for the SD system whereas If you're trying to tune the maf like me you need to do Alot of figuring on your own. Plus there a little faster to begin with.

mtx28

ok, yea, thanks for the input, as i might have said before, i havent messed with computers n whatnot at all before on cars, but i really want to get into it, as it seems to provide a big advantage over carbs(in some aspects, no one blast me for saying that) once you get the hang of what is going on--i havent paid much attention to the prom board, but will definately do so before i get my hot little hands on a(nother) third gen camaro

------------------

• 83 Z28--ttops, 200k miles--very ragged out. sold, thank goodness
• 74 Z28--slightly modded 383, TH400 tranny, not too quick but fun to drive

IROCZTWENTYGR8

iTrader: (1)

"Plus there a little faster to begin with"

SD has nothing to do with making the 90-92 cars faster. They were faster when the cars had SD mostly because of different cams, dual converter exhausts, and other stuff, not because of the SD. They switched to SD in 90-92 because it was cheaper, not because it was better.

There is a test with MAF and SD that TPIS did with 2 cars, 1 with MAF and 1 with SD with the same mods and the MAF car made better #'s and idled better. Making all those adjustments just to get a nice idle has to be annoying, which they said it takes to get it to do that. If any1 wants me to give those results for those who haven't seen that test just ask.


------------------
Looking For:

87 IROC-Z28 350 TPI
The car I want.

84 TRANS AM 305 H.O.
Another car that would be OK to own while I still look for the IROC-Z!!



[This message has been edited by IROCZTWENTYGR8 (edited March 30, 2001).]

IROCZ88

Let me guess, you own a maf car and you're pissed that everyone says speed density is better. Everybody says that the SD cars are better than your car. I can understand where you're coming from. You want to think that your car is better. Well, look at facts just like I did. I bought an 86 MAF system for my IROC, and after talkin to many, many people, including howell efi, tpis, slp, and everyone on this board, I converted to SD. If you think about some of the things Glen91 says, it makes perfect sense.

------------------
'88 IROC TPI 355, fully balanced, 9.75:1 compression, fully ported '70 truck heads(for now), Harland Sharp Roller Rockers, Comp Cams TPI cam, fully ported '90 speed density TPI with '86 base so it fits older style heads, Crane AFPR, Flowmaster 3in. exhaust, Edelbrock TES headers, all emissions equipment is still intact, plan on burning my own chips, many more mods and parts on the way as time and money permits =(
Best E.T. with TBI 305: 16.11 @ 82mph
Haven't been to track with new motor
Won bracket races at Numidia Raceway with my '70 Nova
In memory of Dale Earnhardt, I'll miss cheering for that black #3 on raceday!!!

89FormulaL98

then maybe you could explain why after 93' GM switched back to MAF? if SD was so much better

------------------
89' Firebird Formula WS6 L98, MSD 6AL MSD Blaster, Hypertech chip, K/N filter cone,flowmaster 80 series, hypertech air foil, koni shocks, edelbrock trailing arms

more to come soon.....

My temporary P.O.S. website: www.angelfire.com/il3/DuPageSpeed

BadSS

I'm one of those "MAF guys" that just don't give a flying fart, but it appears both have advantages and disadvantages. However, Mike Davis did a comparison between the MAP an MAF systems that you all can see by accessing his site (referenced in Traxion's chip burning article). Based on what I see and read between the lines,, there is not much if any difference in WOT - repeat - WOT,, at least on his car when it was running in the 13.00 range.

------------------
86 IROC - 9.8:1 - 355, TFS twisted wedge heads, 218/228-110, fully ported GM base and plenum, SLP runners, 52mm BBK, 24# SVO, 88 350 GM EPROM, 1 5/8" Headman headers, 2.5" Dynomax, TH350, 2200 stall, B&M Megashifter, 3.23 peg leg, 245/45ZR17 on 212 Eagles - Best run - 12.53/112.4 on 26x11.5 ET Streets.