Just a title to get some attention, but now that you're reading this I will present my idea.

What does a performance chip do? It adds timing at WOT and increaces fuel delivery by adjusting injector pulse width. I feel that those two main areas can be accomplished with a timing light and an AFPR.

First off, the timing. If set your timing advanced at idle, you have more power at partial throttle and off the line. You can also fine tune for optimun efficiency ( lie you didn't know this already)

Next is the fuel delivery. Preferably, I would increace fuel delivered to the engine by increacing fuel pressure rather than adjusting pulse width, as the fuel pressure method gives better atomization, thus better power. Also, as in the case of timing, you can fine tune with your AFPR.

I expect 13.60s @ 100 mph at the track when making these changes (with good tires). Hope I've been helpful.

 

i can't wait until ed, traxton, or a number of other people tear you up.

so what do you do when you need more fuel but are already at 50 psi? turn it up more and fry your fuel pump? thats why they change the injector width and stuff. set your fuel peressure at like 46-48 psi for best atomization (i think its 46-48 i can't remember off the top of my head) and then adjust your injector width to give you the proper amount of fuel.

as with the timing adjustment. at no or part throttle your base timing means jack. get a scanner to read the total advance at idle. then change your base timing and see your total advance at idle again with the scanner. it'll be the same. what the computer will do is bring up the timing as much as possible until it pings and then bring it down a bit from there or (since i'm not an expert) it has a set total advance value that it will bring the timing to.

now i think you can adjust your base timing to have an effect on your WOT timing since it has set values to add on (again i'm not the expert so i could be wrong)

but either way you are picking a fight you can't win.

Andrew

 

Actually, most 'performance' chips only modify the spark, and only at WOT. Very few chips that you can actually order modify the fuel at all. So yea, you can just change the base timing and achieve what a performance chip does, but you will have a little too much timing at idle.

As for adjusting the fuel pressure rather than the pulse width, well... its your car. Some areas the engine might be rich, and others lean, so changing the fuel pressure wont fix both areas but changing stuff in the chip so the pulse width is less or more in certain areas can fix that. Some things you just cant do on a FI car with a screwdriver and timing light.

 

In some ways you are correct. In other ways you are totally smokin' crack. Hypertech, ADS, JET, and other such chips are crap. Yes, in the case of these chips I believe that you can get better performance with an AFPR, a Timing Light, and some means of judging performance (1/4 track, G-Tech, etc). However, for those people that know what they are doing you can truly reap the benefits of a performance chip. The key here is to find someone that knows what they are doing. These people are few and far between.

Take a 350 SB with BIG camshaft and a MiniRam (my car!). There is no way that you are going to get great performance from just a timing gun and an AFPR with the stock chip. The car will run so incredibly rich at idle and incredibly lean in the upper RPMs at WOT. Furthermore, the timing curve from GM is crap if you have aftermarket aluminum heads like AFRs. The biggest benefit, IMHO, comes with part throttle driveability...
1) A car with a big cam needs a higher idle. If you raise the idle manually with the Throttle body stop screw then the IAC will no longer do any adjustment since you are already over the specified idle in the PROM. So, if you use the mechanism, wave bye-bye to the built in anti-stall routines. Wave bye-bye to the nice smooth idle the IAC routines yield. Wave bye-bye to accessory additive idles.
2) Changing part throttle timing has yielded much much more responsiveness during regular driving. I am not talking about adding to the base timing. I am talking about only adding timing to part throttle curves ... and a lot of timing.
3) Torque converter lockup and unlock.
4) Off idle acceleration. Pump Shot. The MiniRam gives a noticeable stumble and/or backfire off idle due to off idle leanness. The pump shot table fixes this right up.
5) Gas Consumption. Enable Highway mode and you get significant MPG increases. Furthermore, with a big cam and the stock chip the BLMs will bottom out at 108 which means that the ECM cannot subtract any more fuel. Thus, you will be washing the cylinders with excess fuel at idle causing increased cylinder wear and a very crappy idle.

I could go on and on illustrating why TRUE custom chips are necessary on a modified engine. But, I'll stop here. If you have a close to stock engine then you might want to consider using just an AFPR and a timing gun. But, if you have a modified engine (especially when using bigger cams and different style intakes) then a TRUE custom chip will do wonders for driveability and can truly help the fuel CURVE ... as opposed to an AFPR which is almost a static bump or decrease of the entire fuel curve.

Tim

 

I will agree that an off the shelf chip is crap. They do very little.

But let us not belittle the role of the PROM for an EFI engine..... It contains the instructions for the engine which means it really doesn't matter how good of heads and cam and intake you have if you don't tell the engine what to do with them. Burning a true customized chip for your car will definately give you better performance and allow you to tweak a whole world of other things that you obviously don't even know about.

I suggest heading over to the DIY PROM board and just look around at what other things people tweak in the PROM like TCC lock up speeds and Highway Mode settings. What kind of mileage do you get with your car? How much money do you think you can save if you were to get ..... oh ....... say another 10 miles to the gallon? Would that be desirable to you?

And using the AFPR alone to set the amount of fuel your car gets is not the proper way. The problems lie in the fact that the fuel pressure regulator is directly dependant on the vacuum that the engine has at any moment. So when you crank up the fuel to add fuel, you are really only seeing that gain in fuel volume at WOT - leaving the part throttle fuel settings stock. Basically what I am saying here is that it is not possible for you to only need more fuel than what the stock PROM gives you at WOT and not also need it throughout the entire operating range of the engine. And lets keep in mind that most stock bins are actually too rich for a stock or mostly stock engine..... And lets also remember that, as stated by smokin87iroc, you really can only crank the fuel pressure up a certain amount (most people say that about 50 psi is about it) before you begin to severly tax that fuel pump and will burn it out prematurely.

About timing.... When you tune a non-EFI engine timing do you just crank up the base timing to get what you want at WOT? Of course not, you change the timing via the advance settings in the distributor and that is exactly what the PROM does. And I will go ahead and tell you that when you crank up the base timing on an EFI engine to get more timing that you think you need, you will bring it to the point that it will knock here and there and the PROM will pull huge amounts of timing out to protect the engine - essentially, 99% of the time you are defeating your purpose when you crank the base timing up on an EFI engine. You might happen to get lucky and crank it up that certain amount that prevents ping and yields a little bit more power, but your chances are slim to none and slim just headed out the door to get a beer at the pub.

Just do yourself a favor and educate yourself before you make statements like this. There are a lot of people here that have a TON of knowledge about PROMs that are more than willing to educate and help the novices out there. And if you would have researched this subject before you posted this, you would already know the answers to your questions and what is wrong with your statements.

 

By performance chips, I meant those form Jet, Hypertech, etc., which are designed for near stock engines. I dont know of many near stock engines that need THAT much fuel (250-275 rwhp)


Is it just me or did you completely contradict yourself here? You can, in fact, advance base timing without the computer pulling that amount out....just unplug the black wire with the brown stripe and your comp will be none the wiser....also....initial timing does have an inpact on total timing

 

TRAX,

As I added, I meant those chips you mentioned. Sorry for the confusion. I know the benifits of a custom PROM as I frequently visit the DIY PROM board. If I had meant a true custom prom, I wouldnt have posted in TPI.

I also know of the benifits you have reaped from your reasearch and experimentation with you own PROMS, as I have every scrap of useful information (LOTS AND LOTS) you have posted stored on my hard drive.

I just can't believe I spent $180 on a Hypertech before I knew I could burn my own. That is the source of my frustration, as it is useless to me.

 

I'm glad we agree

I also agree

WOW! That was a passive slam if I ever hear one. The fact is that we've had a little mis-communication. I said Perf. Chip meaning Jet, Hypertech, ADS, etc... you thought I meant custom PROM. Since this is not the case, you actually have no idea how much I know about custom PROMS, causing your statement to make you look like an @$$...I hope we can still be friends...

In the future I will use the wording of a politician so that those who get off on flaming others will not victimize me. Thanks Matt !

 

Read this articl from a mag. on this site

https://www.thirdgen.org/newdesign/articles/chips.shtml

just look at what a good chip did on the car tested.

 

Forget the Chips you have mentioned and buy a FASTCHIP. Also don't let the DIY guys get on your case. They feel, everything is junk unless you burn your own chip.

 

Because buying an eprom makes as much sense as sending your carb to someone to be jetted and set the idle mixture based on "engine specs", and then expecting to bolt the carb on "as is".

It may run.......

 

I'd just like to correct you here, that what you are saying defies physics. There are 4 forces acting in the FPR, the 2 springs in the FPR, the fuel pressure, and the vacuum. Regardless of where the pressure is set to, the forces are a fixed part of the equation. One of the springs in the FPR I have not been able to figure out why its there, its extremely low tension and has a small effect on the operation of the FPR and the subsequent readings. Regardless of its intended function, its operation does not vary based upon engine load. The other spring is basically to counteract the fuel and set the pressure at a specific point, beyond that it allows the metal piece at the bottom of the FPR to come off its seat and release pressure to the return line. The operation of this spring also does not vary based upon engine load. The supplied fuel pressure also does not vary based upon engine load. The only thing that varies with load is vacuum, and at 2 different pressure settings in a properly operating system, the force applied by the vacuum is the same in either case at WOT or any other point between the 2. The pressure at the discharge side of the injector is also a quantity that will be the same regardless of fuel pressure. The 2 values are not inter-related in any way. Any attempted correlation between the 2 introduces a variable in the equation that isnt there, aside of fuel pressure delivery (read: weak/bad fuel pump), fuel containment (read:leaks) and injector maladies, or some other problem I might be missing.

 

i did misunderstand that you were talking about performance chips from companies and i thought you were talking about chips in general

but
yes you can disconnect the est wire and put in whatever total advance you want and run it with the wire off i guess.
but your base timing will only affect your total timing at WOT not at crusing speed or at idle. i tried it with a friends car. he was given the wrong harmonic balancer and the timing mark is way off from where the timing marks are. so i tried to set the base timing by looking at the total timing at idle. well no matter what we did it would still set the car at 25 degrees of total advance at idle.
so base timing had no effect on his car at idle.

Andrew

 

[QUOTE]Originally posted by MelloYello
Well first off, it was not a slam. And since you have wrongly assumed that I was slamming you, you now appear to be the @$$...........

Secondly, if a mis-communication is all that happened, than why continue in the manner you did? Who is getting off on starting a flame war here? I agree - a communication problem was present and only because of the way I interpreted your original post. If I have wronged you, than would it help if I said I was sorry?

Well, maybe if your post was a little clearer.......... .......... And you wouldn't need to post this topic in the first place if you had a decent base of knowledge of PROM burning.

Stop being butt-hurt..... How about in the future you just make your posts clearer and stop taking things personally. Your original post was so riddled with generalizations and answering of your own questions that I felt compelled to point out the parts of burning a customized chip that you seemed to miss. It was nothing but an attempt to educate and help.... And it was not apparant from your original post that you were only talking about ADS, Hypertech, and the like PROMs. If you were specifically talking about those chips and it was evident from your original post, I wouldn't have bothered replying since your statements would be virtually 100% correct. I may have come across crass, but I assure you that none of it was a direct attack on you and I was meerly trying to help you. If you wish to take things personally, I will remember not to attempt to help you in the future.

Jeezz..........

 

OK. I'm confused here....... Where I am coming from is the setting of an AFPR. You set it with the vacuum line off and increase the pressure on the spring that seats the valve that limits the amount of the supplied fuel pressure that gets to the injectors. This also affects the amount of fuel volume that the injectors deliver during their individual duty cycles since there is more fuel that will flow through the pintle or disc area when the injector is triggered. The pressure of the fuel on the discharge side really has to vary depending on the pressure supplied to the rail side until the injector goes static.

Now this means that when the vacuum line is replaced onto the AFPR after the desired pressure setting is found, it will lower the fuel pressure as the vacuum supplied to the diaphragm inside the FPR body will also act on the FPR's valve and pull it off its seat even more which will lessen the pressure that is supplied to the fuel injectors themselves and increase the amount of fuel that is sent bact to the tank through the return line.

So this means that the fuel pressure will be lower than what you set it at with the vacuum line off during low throttle - high vacuum conditions which means less fuel pressure at the injectors and in turn, less fuel volume delivered to each cylinder per injector cycle. So the setting that you create with the vacuum line off will be present only at WOT or extremely low vacuum conditions.

So if a person needs more fuel volume for ones engine setup, the AFPR will not be a total fix.... right???

What am I missing here?

 

What you said was that at WOT there would be a fuel gain, but at part throttle the settings would be stock. This isnt true. Lets say you start with your fuel pressure at 45psi vacuum off, 35 with the vacuum connected. In a properly operating fuel system, if you increase the fuel pressure from 45psi to 50psi with the vacuum off, and then reconnect the vacuum, you will be at 40psi. That is going to increase the flow rate of the injector at part throttle since there is a 5psi increase in pressure at part throttle (or any point at all for that matter). Is it the fix all if your starving for fuel across the operating range? I highly doubt it. Some areas will need more fuel than others, and messing with the fuel pressure cant fix that. I've been messing with 3 different cars lately and they are rich at times, and lean at others. An AFPR isnt going to help me. I can fix one spot, but not the rest. I would say given the number of variables in a car, if you want a 'perfect' tune, you cant do it with an AFPR.

 

One of the great things I prefer about burning my own eprom is I can select the fuel pressure I want to run (and tune accordingly in the eprom) than try and find a fuel pressure that makes the car run properly (generally WOT).

I think most of us still subcribe to the theory that higher fuel pressure makes for better atomization without going so high as to prematurely burn out your fuel pump. Selecting your preferred fuel pressure and tuning your eprom accordingly is by far the best way to go.

 

I realize that this is getting into the Prom area, but I have suspected that I could benefit from some significant timing changes. I am running a "mild" Speed Pro cam and Edelbrock Heads, but an essentially stock '89 timing curve. I've read many posts that indicate that aluminum heads require quite different timing curves, but no specific directions. What changes should I make? Is there a good .bin out there (insofar as the main spark is concerned) that would be a better starting point? FWIW, I am not using the famous ARAP bin because of it's aggressive spark curve.

 

Ahhh....... gotcha.... yeah, what I meant was that cranking up the fuel pressure will give you the greatest gain at or near WOT and will leave anything other than that closer to stock - as in the increase in pressure will not be doing nearly as much at part throttle - high vacuum conditions to increase your fuel needs as it will at WOT........ Which means it isn't going to fix the problems that a car might have. My fault on that one.....

There it is in a nut shell.

 

Well I would say that getting the ARAP is a great starting point for almost all MAF cars. I have succesfully gotten it to work on even iron headed cars with little or no changes to the timing figures. It is a little aggressive at times, but you can back it off a bit if you want here and there IF you have problems. My setup with TFS 23* AL heads was pretty much fine with the stock ARAP settings aside from some high-load - low throttle - low rpm conditions so I just went in and tweaked those figures and I am having good results now with my modified ARAP. You can always use the max timing retard at WOT stuff to help get you where you want as well, but it is a bit dangerous if you aren't well-versed in PROM burning. And in general, an AL head will want and allow you to run more timing than an FE head - which is what the ARAP has over stock along with some other tweaks.

Good Luck!!
Laterzzzzzz

 

Grumpy (and others) has said that aluminum heads want or work better with less timing. Advances in the low to mid 20's seem to have been recommended. I presume that this is in the high load regions, but I don't know that for sure... Running lots-o-timing during cruise still makes good sense to me.

 

Actually, the times that I have heard Grumpy (and others) talk about not running much timing it has been in regards to the stock iron LB9 or L98 heads. Most aftermarket aluminum heads will come with instructions that will tell you what kind of timing they respond well to. For example, the literature that came with my TFS heads and my friends Brodix AL heads both say that 36* of total timing is a good place to start. That would be 30* of advance if you have 6* initial.

 

Matt is correct. It's the GM heads that tend to want less timing. More specifically, the newer heads that promote "swirl and tumble" and tend to have smaller combustion chambers.

Older GM heads that don't promote this "swirl and tumble" and many of aftermarket heads do tolerate a lot more timing. My friend has a 383 with AFR 195s and those heads tolerate a lot of timing. With the AFRs, we are finding 36* at peak TQ is working quite well. Come the spring he is going to "tinker" with the timing a bit more to find the "optimum" timing (whichi isn't necessarily the max timing the heads can toleratre).

 

I WILL TELL YOU WHY I HAVE A CHIP IN MY CAR.

BAECAUSE IM TO LAZY TO DO ALL OF THAT CRAP YOU JUST SAID.

MY CAR HAD ALL OF THAT DONE TO IT WHEN I BOUGHT IT.

THANK YOU.

 

a PROM adds timing in various places, not just WOT.

Part of the reason why guys who burn their own are finding gains is that GM can't sell a vehicle that detonates itself to death because stupid people buy them. But those who burn their own can kick up some Part throttle timing to gain mileage / power because they know to get out of it if they hear knock.

You have to look at the whole window. A PROM gives greater pulsewidth, yes, but more importantly, you can put it where you want it. Idle in a blown car needs leaned out compared to\ mid & top end where you need more fuel. So you can kick up the fuel level where you want it, not just across the board (which is what an AFPR does, which is what you accuse PROM's of doing) On a smaller scale a hard running RPM car has the same situation - see Trax's post.

Picture a pane of glass.

Then picture a diamond cut by a jeweler with 112 facets.

AFPR is one dimensional. So is base timing. a well done PROM is many multi-dimensional.

Sell your Hypertech chip on fleaBay and learn your lesson which you clearly have. Why pull everyone out of the woodwork like this?

You already did. Be glad that those who get off on flaming haven't pulled out all the stops

Troll.

 

I have one question,my engine is totaly stock,is'nt the hypertech chip at least better than the stock chip

 

It's really amazing how quick people are to frag each other on this board. The first reply to this post frags the quy with the threat of others "tearing him up"!
Then it goes into two pages of he said/she said.
I thought the intention of this board was to educate and not belittle. Sheesh, check the ego's people.