I am considering purchasing the kit to burn my own chip as seen on the DIY Prom board. I was wondering if anyone has done this? I can have a custom chip burned for me at a shop in auburn for around 300 bucks. This includes testing it on the dyno for best performance. I think he will reburn the chip for me for 50 bucks once i rebuild my 350 to a 383. The kit for the DIY Prom is about 250. What do you guyz think?

 

I'm going to get the equipment to do this when my next paycheque comes in (hey, I'm a student, I live payday to payday in the summer).

There are some things in the PROM burning article that are a bit outdated. Here is a simple 2 transistor circuit to interface with the ALDL:

http://www.andywhittaker.com/ecu/aldl_hardware.htm

And you can get a burner from here (not sure how good it is, lots of others use the xtronics one):

http://www.logicaldevices.net/suppor...usky/index.htm

And if you are even going to listen to one piece of advice from me, ever in your entire life, *buy Flash ROMS*, do not use EPROMS. I'm not sure how much electrical knowledge you have, but EPROMS are a real pain in the *** , and they are outdated technology. Flash ROMS are 1000x better.

 

You better just start over like willie here:

http://willie.camaro-firebird.org/



Too hi-tech for me craiger, I would be happy to have a timing light at this point !

Don

Terroists Win !
CT get the chicks
(inside joke)

 

Cool! When you get it figured out, you can burn me one!!!

 

I've talked to Willie before, nice guy. I think hes some kind of aeronautical engineer or something. His IROC is Schweeeeeeet! BTW, I think those pics of his engine are old. I believe he now has an ATI Procharger.

[This message has been edited by RSFreak (edited June 18, 2001).]

 

What blows me away (70's term) is that his mill is a 305

Don

 

Yeah, thats ballsy! His custom lettering and graphics are killer too. I once asked him how he did those, but I have since forgotten. I am going to do his front turn signal mod (or ask if he'll do it for me). Those look nice too.


[This message has been edited by RSFreak (edited June 18, 2001).]

 

Get the burner for sure. If it's less than having someone else do it, go for it. Gives you bragging rights too. That would be too cool to have one of those. If I had a computer in my car I'd definately get one. The more toys the better.

 

This got me thinkin (uh oh) so I did some digging and found this stuff:

All Chips Are Not the Same.

The engine calibration chip in the ECU is referred to as the PROM. It contains the program that runs the engine. Due to EPA concerns most performance chips only alter the WOT fuel and timing table, leaving the idle and part-throttle values stock. If you have a slightly modified car this is usually sufficient If your EFI ride is radical, then you will need to have a custom calibration done or install an aftermarket user-programmable ECU such as the ACCEL/DFI system.

Accel/DFI CALMAP Instruction Manual:
http://www.cruzinperformance.com/accel/


Don


------------------
1985 T/A WS6
Recaro Seats
58,000 smiles
TPI T-Tops
3:27 Posi
K&N
https://www.thirdgen.org/rides/index...ew&rideid=3080

 

Yeah, I burn my own proms all the time. What do you want to know?

 

The Holley Commander 950 is supposed to hook up to a TPI wiring harnes and provides for an interface with a laptop computer. That would be the hot ticket and talk about easy to use! No chips to change and you can make adjustments on the fly while you're driving (and on the dyno). Since you're using a supercharger you could install a 2-bar MAP sensor and larger injectors and completely tune your fuel and ignition maps and chuck the FMU. You'd pick up about around 50 Hp. It also integrates with MSD ignition systems for full control over timing and has the capability for boost timing retard.

[This message has been edited by QwkTrip (edited June 19, 2001).]

 

Glenn,

I have a 91 Z28 with a supercharger and I know a few guys who are squeezing a full .5 off of their 1/4 mile times by burning thier own chips. Is it an easy thing to do? I have a friend who has a shop with a dyno who will burn me a chip for 300 and any reburns due to upgrades will cost 50bucks. I think the kit in tractions artilce cost just around 250. Just looking for some adivse...any help would be greatly appriciated.

 

Craiger, burning your eprom is VERY EASY to do. Getting the right values is another story...but with testing, testing and more testing you WILL get amazing results.

I have talked to a lot of guys who actually burn eproms as a side business and they will all say the same thing, that to get a GREAT eprom, you need to do a lot of "hands on testing". Getting someone to burn you a "formula eprom" based on a set of specifications will get you a reasonable eprom, but it will most likely not be optimal. Optimal is where you get your maximum performance, maximum fuel economy and least emissions. It truly is a win-win-win situation.

Go to the DIY PROM board and click on Tim's Prom Burning Artile on the top of every page on the DIY PROM Board. It tells you all the equipment you need. The only thing it does not discuss is replacing your eprom with a Flash Prom (AT29C256), which allows you to erase/reprogram completely with just the burning itself. No more UV eraser. PLUS you don't have to wait 15-30 minutes for the eprom to erase. All done in less than a minute.

Tuning the SD system is very straight forward (I think it is even more straight forward than a MAF system), but it is time consuming. MAF is quick to adjust but you don't get the same precision as you do with SD.

The biggest problem with either system is that neither work well with a Supercharger. MAF gets maxed out at 255 gm/sec, while SD is limited to 1 bar. You can cludge the SD system to work under boost farily easily and there are two different methods to do this.

I am currently looking at re-writing the code of the SD system to handle a 2 bar MAP sensor properly, but since I have no direct need and this is done totally on my own free time, it will get done when it gets done. But that is really the only effective way to make the SD system work with a power adder properly.

The advantages of burning your own eprom far outweighs buying an eprom. Most eprom writers ONLY concentrate on WOT (which for most enthusiasts is fine). But there are so many things that you often need to tweak in Idle and Part Throttle, that you need to capture information with a scan tool and then test. This making modifications "on the fly" is for the birds IMO.

You need to make notes and monitor EVERYTHING when you make a change. You change something on the fly, it MAY fix one thing or run better in another area...but not in some other part. Or a certain condition may trigger an SES code. I made one modification that would only show a problem after about 15 minutes of driving under a load condition. You would never have seen it if you had just done it "on the fly". You would have initially thought the change was a good change, when in fact it affected something else.

Lastly, I like having a library of diffeent "evolutions" of my BIN so I can see what I did on one change to the next change. After a 100 or 200 different "burns", you lose track really fast.

But you can get fairly good results with the SD prom even with a Supercharger. You just have to be aware that when you are in a boost condition, that you are "in the dark" and making changes on a trial and error basis (though you do that a lot anyways @ WOT).

The simplest and most effective solution that we have found for SD applications with a Supercharger is to use a 1 bar MAP so it properly controls your part throttle, but at WOT (actually called Power Enrichment) you start to add a LOT more fuel than you would typically do with a Naturally Aspirated engine. I typically add 10% extra fuel @ WOT, but with a Supercharger, we might anywhere from 25-50% more fuel, depending on the boost levels.

This is similar to how a FMU works. What you have to do then is watch your spark plugs VERY CAREFULLY.

Frankly, for a person wanting to modify an EFI engine, burning your own eprom is just important as having a set of socket wrenches IMO.

 

Glen, good thing i have an fmu! Thanks for the info. Where can i go to find out how to understand the values i will get from the different chips?

 

Craiger, an FMU is a bandaid solution to fuel delivery. You can burn PROMs day in and day out and until the day you drop the FMU you will not see the big power gains available through custom tuning. You need a control system that can accomodate a 2-bar MAP sensor, be capable of calibrating timing against manifold pressure, install properly sized fuel injectors, and then tune the car on a dyno.

 

Currently, the BEST solution at this time for a Supercharger/Turbocharger application is to convert your 7730 ecm to the 749 (SyTy) system. It is designed around a 2 Bar MAP.

There are a number of "cludges" to make SD work with a 2 Bar MAP, but they are far from optimal and introduce their own "problems".

If you are serious about wanting to a good solution for you Supercharger, then go to www.syty.org and learn about the 749 ecm. As I understand it, it is not a difficult conversion.

[This message has been edited by Glenn91L98GTA (edited June 27, 2001).]