1989 Firebird Formula 350

Stock L98 Block, Alston Subframe Connectors, Hypereutectic Pistons, Forged Conn Rods, Fluidampr, ZZ4 (208/221@.50) Cam, Aluminum Vortec (Fastburn) heads, Dyno Don 1 3/4 Coated Headers, Dyno Don Off Road Y-Pipe, Hooker Cat Back, Monza Exhaust Tips (The Hooker ones were TRASH), Corvette Servo, Transgo Shift Kit, 1.5 Ratio Roller Rockers, Edelbrock Vorted Base Plate (intake manifold), AS&M Runners, Accel 24 lb Injectors, and other cool stuff.

so, i think ideally, i would want to get a custom tune, where they burn a chip "in house" while optimizing mechanical perameters like fuel pressure. but that will probably cost about $1000 bucks. plus, i'll have to drive (more like trailer) the car to the big city (Seattle or Tacoma) because of the vaccum deficit and its effect on braking. on the other hand, for $ 350 i can get a custom chip for my combination (Ed Wright, Fast Chip.) that should at least smooth out my idle, provide sufficient vaccum for the brakes, and lean out the fuel mixture, so that i can commence driving the car.

therefore, my question is, is it worth it to wait and haul the car (170 mile round trip) and have it custom tuned, or will i most likely be more than happy with a custom chip. and, is the chip something that the custom tuning shop can work with or would they have to insist on burning their own chip?

all input is welcome. any input backed by expertise or experience would be especially appreciated.

 

! would do it myself. do a search lot of info on prom burning.

 

thanks, but not the answer i was looking for.

also, will the right chip or tune fix the problem with the brakes or do i need to look into a vaccum reservior or possibly a new brake booster (maybe mine is bad)?

 

A custom tune shouldnt be anywhere near that much!! Dyno tunes usually are under 500 bucks. Chip and adapter for the ECM costs 55 bucks. To "tune" the car, the software is free and the tuner will need ALDL cable for 80 bucks and Burn programmer for 80 bucks. Rest spent would be dyno time at around 100-120 an hour. It would only take an hour to tune that car...max!!

Who or what shop would be doing that tune? If people are paying 1000 for these tunes I need to get into that business

That combination isnt too far off a ZZ4 spec but with better heads. A stock chip should run ok on that setup but with 24lb injectors, its gonna run abit richer than normal since stock chip has 22 lb injectors.

A mail order tune from PCMforless or Ed Wright SHOULD beable to get it close enough to drive reliably but you still will want to put it on a dyno and see what it does. I would not put a ARAP based tune in it with the fastburn vortec type heads, as they dont need the aggressive timing. I'd have them start with a stock bin like a AUJL or similar with a conservative timing table. IF they have done vortec head builds before, they will know the timing tables.

It should have PLENTY of vacuum for power brakes. NO reason it shouldnt idle stable and have good vacuum.

 

I have to agree with Orr89rocZ. A place like Pcmforless, they should be able to get that tune really close. Those injectors are too big for your car also without a custom chip.

 

[quote=Orr89RocZ;5017439]thank you. i really appreciate the advice. this is exactly the type of information i'm looking for. a guy quoted me at $600-$700 for the chip w/ tune.
yet here we are. the idle will eventually level off at about 8-900 RPM. but when you fire it up, it wants to jump up to about 2500. and it will idle at like 20 MPH. if your doing 50 and let off the gas, it will idle at 35 MPH all the way home. and the vaccum for the brakes disapates very quickly: at 50 MPH or even 25 MPH it stops fine, but at idle after one or two application of the brakes, its like the booster goes kaput. but then, give it some RPMs and the braking will return.

 

tune should only be $150 max! mail order

 

what do your brakes have to do with your chip? Chip controls the Air/fuel mixture

 

I suggest fixing your braking problem first, then give one of the companies listed above like Fast chip a call and order a custom burn chip for $150 or less to get you started.

 

That doesnt sound like a tune issue but more like a bad vacuum leak? High idle like that is NOT normal and even on a stock tune, it shouldnt be THAT far off with that motor. I suggest looking around the intake/runners/TB for air leaks and also checking the brake booster. It may have a ruptured diaphragm inside and thus causing no vacuum or even a huge leak. Also double check base timing.

You'd be surprised how well some of the stock MAF tunes from L98's idle on cars with big cams/heads. I've tuned a few motors now and didnt have to make all that many changes to get a "stable" idle. MAF does a fine job.

With the proper air fuel at idle and by playing with timing, you can change the amount of vacuum you see at idle. Best way to tune idle air fuel and timing is actually to put on a vacuum gauge and tune for best idle vacuum. Usually this comes from higher timing. Too much timing can cause some overheating issues and there comes a point where idle speed is forced higher because you have alot of timing. A mild cam with ALOT of timing at idle will not idle at say 700 rpm. It may be forced to 1000 rpm, but it will make ALOT more vacuum than when tuned to 700 rpm. Its all in how much vacuum you need to have and how much idle speed your willing to run. You can see this effect by disconnecting EST wire. That drops timing from 20 to 6 deg. Idle will drop/stumble. Bump base timing to 35-40 deg. IDLE will shoot high.

 

[quote=Orr89RocZ;5017674]

right. i wanted to look into that. the booster was the only thing on the braking system that wasnt replaced, and the car sat for a long time prior to this build. but, i figured that if the brake booster was bad, it would have little to no braking all the time, not just at idle speeds after one or two applications of the brakes, right?


well, i was a little suprised with the problems i'm having because i didnt think that the ZZ4 cam was that aggressive.

Quote:

With the proper air fuel at idle and by playing with timing, you can change the amount of vacuum you see at idle. Best way to tune idle air fuel and timing is actually to put on a vacuum gauge and tune for best idle vacuum. Usually this comes from higher timing. Too much timing can cause some overheating issues and there comes a point where idle speed is forced higher because you have alot of timing. A mild cam with ALOT of timing at idle will not idle at say 700 rpm. It may be forced to 1000 rpm, but it will make ALOT more vacuum than when tuned to 700 rpm. Its all in how much vacuum you need to have and how much idle speed your willing to run. You can see this effect by disconnecting EST wire. That drops timing from 20 to 6 deg. Idle will drop/stumble. Bump base timing to 35-40 deg. IDLE will shoot high.

i've done this proceedure on my Mustang (also an '89.) in that case, it turned out the problem was just the throttle plate position screw. i will be very upset if this is in large part a problem with the TB or linkages thereto. i think i might have to have my transmission guy take a look at those linkages (as i wouldnt really know exactly what to look for.) i need to take it to him anyway because it shifts from 1 to 2 waaay to soon.

thanks again. you've given me a place to start. check for vaccum leaks. i'll also have those linkages checked out ASAP. and look into the possibility of a bad brake booster.

other than that, i still need to decide whether to take the car to get a custom chip with tune or just get a mail order chip.

 

[quote=ninetyone;5017658]

yeah, been trying to wrap my brain around that. the shop chalked up the braking and idle issues to the loss of vaccum (which i didnt think would be noticeable as i didnt go too radical on the camshaft), and the confusion of the CPU by the new combo.

get me started? dont say that. i wanna be gettin finished with this project, man. not getting into a whole [expensive] can of worms to get my costly engine build to run right.

i will look into a couple of things that i've mentioned. as far as the chip, i'd like to go mail order seeing as how i'm pretty well cleaned out already by this project, but at the same time, i have heard a few horror stories about the mail order chips always being wrong and causing the car to run improperly; sending chips back and forth through the mail, ect.

thank for the input. it helps.

 

Where is your timing set at?

 

Well you should have the linkage and TB sensors all checked out. Verify the TPS is set right, the IAC is working right and not sticking open, and that the TV cable is adjusted right. Once thats done, you can try to get a tune but tune wont help if the car isnt mechanically sound to begin with.

You are right, that cam is NOT that aggressive and it should be working alot better than it is. So it makes me think there are other issues at play here.