canuck buick

I have heard a lot of railing against these chips but if your prom is screwed are these an alternative, has anybody had a good experience.

CREWZIN

I've had one for about 15 years. It was custom made from a place in California called "Corvette Consultant". Don't know if they are still in business anymore. Had to give them all kinds of information including any modifications I've done. It only comes into play at full throttle but it makes a hell of a difference when I floor it.

The biggest pain was standing on my head on the passenger side to take the computer down. Chip went in without any problems and then down again to the floor to put the computer back up.

jv9999

My '87 came with a Hypertech. It never idled right so I replaced it with an OEM one. Idles perfectly now and seems to pull just as hard.

JrRifleCoach

Off the shelf tunes are base lined from someones else's motor.
Custom tunes are based on your motor in your environment.
This ain't tires.. Its your engine

QCVette

I had an '87 that I put on a flowmaster exhaust, air foil, 1.6 rockers and it would bog a little from low speeds.

With an SLP chip it ran fine.

FASTAZU

I agree get a custom dyno tune or road tune.

Klondike

Don't know if they have one for the C4, but my buddy had a module that plugged into the OBD port on his C5. His was an automatic and you could tune the shift rpm points and firmness of the shifts. I thought it was pretty neat to be able to customize your transmission by just plugging in under the dash and pushing a few buttons.

aklim

I gained up to 20HP with the SLP or was it Hyperjunk when they first came out. Huge emphasis on "UP TO". Any number including a loss is fair game since negative 30 is within the scale.

Gibbles

When i first got my c4 i found a hypertech chip on ebay for what seemed to be a good price.
hypertech stated it would change when the fan came on...
Later i found out that my computer does not control the fan in my year.

Hypertech= liars

And it did seem like it helped the car, atleast in my head...
​​​​​​​and i still have it, maybe I'll toss it on ebay with my ecm and the original chip.
(Now i run an ebl flash ecm)

aklim

I go by a simple rule. If it is cheap and easy, it won't work. So you have a switch in the heads or what turns it on?

​​​​​​​I wouldn't. Sell it to the next sucker. I'd keep the original one for reprogramming.

Gibbles

Yup, switch in the passenger side head.
and my new ecm can control the fan, i ran a wire to the relay since i hate having to buy a new switch if i want to change the fan on and off temp.

​​​​​​​And really no point to keep the old ecm, i had to convert my wiring harness to a different style of plug.

DMITTZ

If you have made changes to your engine etc... and require a custom tuned PROM/chip contact Scott Hansen of Tuned Port Induction Programing Services, he does a great job and will taylor the tune to your needs based on the information you supply. He did my custom
​​​​​​​PROM and did a wonderful job of it.

Here's a link to his website:
http://scotthansen.net/



Just as a note to the OP a 'stock' engine won't really benefit or need a custom prom tuning or an after market 'chip'. Custom programing/tuning is used mainly to account for mechanical modifications to the engine such as cam swaps etc... which require changes to the tuning to work properly.

aklim

I would say that even intake and headers could benefit from a chip. I had a 91 F-body that was bone stock. Put Superram intake and Accel Tri-Y headers and it did feel like something was lacking although better than stock. Brought it to Lingenfelter who was alive then. He tuned it and that improved drivability vastly.

​​​​​​​If you have done some decent mods, I'd say get a dyno-tuned chip. Only way I would use mail order is if we could datalog and make improvements. On my truck, we told the tuner what we had, he set up the program, ran it, datalog, rewrite the program a time or two to dial it in. Otherwise it is a guess to estimate what the motor does.

John A. Marker

Before I discovered the Corvette Forum, I bought a Hypertech chip for my 85 because it promised a instant up to 50 HP...just plug in and run. Who doesn't want another 50 HP. I really didn't "feel a seat of the pants" difference....but advertising has to be correct! I noticed that I would get the dreaded engine PING at times. I started to try different brands of fuel, different octane ratings, added octane boost and finally just started to play with the distributor base settings. It still never went away. A couple of years later I ran into Tom Wong on the Forum and arranged to drive the 800 miles up to Vancouver Washington to have him do a tune on the car. He told me up front not to expect huge gains on a basically stock engine. I gave him a list of all the modifications that I had made. Spark plug brand and gap. Distributor setting and everything I could think of so he would no start the dyno tune in the dark. He started off with a base line and discovered that as you accelerated the engine leaned out. He looked at the chip tables and discovered the Hypertech chip was REMOVING fuel as your speed increased. Damn, that sure explained the PING that developed. He tuned the car and burned a new chip. I threw away the Hypertech! Never an issue with PING again, increased fuel mileage, much better acceleration and idle. It was like a different car.

If your really set on a new chip, don't get something off the shelf from some supplier. Get a dyno tune or work with one of the reputable tuners and do data logging and dial in the chip to your car. Data logging as you have your chip built and mailing it back and forth as it is tweaked is a PITA, but for many of you out there it is the only option open to you since tuning for C4's appears to be a lost art.

My son has the 85 now and has added headers and swapped out the older AFR 180 heads for newer AFR 195's. The car is still running off the tune that Tom did on the older setup and is running 12.6 now thru the quarter mile. It will get back into Tom for a new chip to fine tune the new setup. The car should be 12.5 or faster.

mickey5

If a stock prom is destroyed by static electricity how do you get a replacement? Does anyone provide a service to burn in stock codes to a replacement chip? Are unprogrammed chips still available?

Sorry to butt in but I've never seen these questions addressed.

Paul Workman

A stock chip (calibration) for a stock motor, like Wong said; don't expect much.

Although Corvette doesn't custom tune each Vette coming off the assembly line, they do have a well established calibration model for FUEL, AIR, SPARK (timing); the tools for getting the most from any motor. And, to deviate from the stock calibration can lead to relatively small advantages before performance compromises (e.g., ping?) crop up.

To coax the best out of any motor is best done on a dyno by a skilled tuner. That way any performance "left on the table" might be realized on a specific motor and attendant modifications (e.g., cams, headers, etc), without compromising the performance negatively.

This is why many "off the shelf" calibrations promise "up to" gains, but in order for 'one size fits all' applications, there is little practical improvement to be had and still keep from destroying customer's engines...which has happened.

Example (taken from shooting sports): If you are a competition target shooter or hunter that is engaged in handloading your own ammunition, you know why you never want to load ammo for someone else's gun w/o having access to their gun in order to work up a safe load for that specific gun. And, conversely, don't expect to gain much performance increase from "off the shelf" or reloaded ammo for the same reasons "off the shelf" tunes are seldom exceptional: they are constrained by the liabilities of the unknown.

DMITTZ

Yes, Scott Hansen has spare PROM's for our cars. He supplies you with a PROM when you get him to burn you one and does not even require you to send him your old one.

His company is 'Tuned port Induction programing services' as I mention above. He is very affordable because he is just doing this to help out the C4 Corvette community. Visit his website, he's a great guy.

aklim

Further to that, I don't care how good the tuner is. If he isn't data logging or dyno-tuning, he is either leaving something on the table or is guessing and thus recklessly endangering me. Pass. If they can send you a chip based on what you tell them and call it good, I would not go to them. Many of those I talked to have said they know based on the mods. I would call BS. For liability reasons, you would have to back it down. If you can maximize it, you are God or reckless.

aklim

Perhaps but does he tune in the program and how? Going off the customer saying "I feel...." is meaningless. Unless he is practiced at dyno-tuning or does repeated data logs, it isn't the optimal solution

cv67

Well said

fell for the hypertech thing. Didnt run any better or "worse" just turned the fans on earlier which was all I wanted.

Custom tune is where its at but if its pretty much stock leave it be