fnseeker

Well thats not totally true. I placed a hot cam in my 90 6spd 3;42 gears. Now if I am under 84 mph or less than 3000 rpms im 6th. My car just bucks like crazy. No low end torque there at all. Even in first the car feels lazy until 3000 . It comes on like an animal at 3000 rpms. I have tried retiming this to help, No luck. Any ideas?
The car still has stock runners, and a ported stock plenium and intake.

bogus

ugh... it sounds to me like the cam wasn't installed right. It's off a tooth or 2... or, you have a vacuum leak from hell.

I will be curious to see what others say.

But the idea of a hot cam with a ported stock intake is a bit scary.

FELNGR8

The very long runners of the TPI intake definitely mis-match with the HOT Cam. If you want to keep that cam you need a different manifold, for example the Miniram, or a modified LT1 manifold.

My Hot Cammed LT1 with ported heads and 3 inch exhaust will pull up smoothly from 1000 rpm in 5th. I can cruise easily at 1500 in 6th. Mine is no torque monster down low and does come on the cam at 3000 like you describe. But I can cruise like a stock motored car.

Nathan Plemons

You've either got some installation issues, some tuning issues, or the hot cam really does suck in the TPI.

I'd lean more towards tuning issues. What if any tuning has been done since you installed the cam?


BTW I agree with the driveability of the cam, it is one of the main reasons why I recommend it so much. I can cruise 45-50 MPH in 6th gear with a minimum of cam surge. 70 MPH on the highway is just as smooth as stock ever was.

vader86

I'm leaning towards tuning problems as well. I can think of one other person who installed it on a TPI and he didnt complain of problems this bad, but you will not have the low end you once had because the cam is mismatched to that intake.

Who did your chip, or have you not done that yet?

Nathan Plemons

I just spoke with one of my friends who did the Hot Cam in his carb SBC. He said that his driveability greatly improved after he set his base timing up to 15. It might be worth a shot, set it up and see if the driveability improves at all. Drive it EASY though incase that is too much, your knock sensor should keep you safe. Be sure to disconnect the ESC when setting the base timing.

Duane Hawley

Actually you would be suprised at how good a stock tpi works with a nice cam.I ran a zz-x cam which is bigger in my 88 with stock stall.Upper plenum ported and 1 5/8s headers.With retuned chip car ran 12.00's all day long and had one bad *** sound.Braking at idle was ok but not great.I wouldn't recommend it for a daily driver!
Thanks,
Duane

tjwong

Someone here did use a HOT cam in their TPI L89. He installed it with 4 degrees of advance. My suggestion is to bump the base timing up about 4 degrees to see if that helps. However I do also agree there is a tuning issue because you have a 90 which is a speed density strategy. In this case where your engine used to idle around 35 to 40 Kpa it is probably now idling at around 50 to 55. Which means its fueling for this region rather than where it was which is usually richer. So in saying that a custom chip is more than likely going to be needed.

fnseeker

As I stated earlier. The timing has been changed many times. Is currently at 8 deg advanced before the wire is reconnected to the cumputer. Runs approx 13-15 deg advanced connected. TDC has been rechecked over and over.
The chip was done by Jesse Azzato (ski-down-it) from here on the forum.
I forgot to mention, that I now have a single piece fly wheel. But I don't feel that has any connection here.

TRaj2327

I'm no L98 genius but maybe your motor just can't breathe under 3000 rpm and the fact that it pulls like mad over 3000, well thats just your power range on that cam. You oughta be able to rev a little higher too with some new top end components. Sounds a lot like my buddy's '89 Trans Am, but he had a 305, now 383.

bogus

The TPI is designed to breathe below 3k... it just won't breathe above 5k...

93 ragtop

That was my problem with mine. Idle and part throttle was way rich. Wide open throttle was fine even with the stock tune. If you get some scans on it such as datamaster that will tell you if the tune is way off. If you have a laptop you can download the program for free and use it 20 times. Only thing you will need is a cable.
Get someone such as TJWONG or Alvin at pcmforless to program your chip. You need someone with speed density experience.

Nathan Plemons

I see one fundamental problem but I think recent forum rules prevent me from saying what it is. I'm sure you can figure it out, good luck.

FELNGR8

You need a real tune on a dyno for this setup. That's what got my car running smoothly in the lower revs without losing the high end, I speak from experience.

But even the use of a dyno is more controversial than it should be.

Red Tornado

Right now you have 2 problems. The lesser of the two is the FW. If you have an ultra-light aluminum one in there, this has alot to do with the lost feeling of low-end torque from a dead stop. This is unavoidable with such a light FW. I did this last year and had it ripped out after 2,000 miles. Personally I despised it. It was a Fidanza.

Its very likely your big problem is that chip. When I saw this thread I almost dumped in my pants. Please do yourself a favor and have that chip verified asap via a .BIN file comparison between stock vs. the custom. If he didn't fuel up your lower VE table (tha Main Fuel Table, aka: partial throttle all the way up but not including Power Enrichment)), this is your problem. It will buck and carry on because you are running lean due to fuel starvation. You may or may not be experiencing pinging/detonation since you've only ported your stock intake + you have a larger cam, and the increased air vs. fuel mix may not be quite enough to cause this. You'll have to verify this.

I suffered a great deal of expense because of the utter lack of competence from that certain "tuner". I have a perfect right to post this. If someone did something terribly wrong and won't own up to it, this person must be sniffed out and publicly exposed. I don't feel I'm breaking any rules by posting my experience. I suffered very real and extensive engine damage directly attributable to this tuner's FRAUDULENT recalibration. This IS a fact. IMO he didn't do it on purpose, he didn't tune it right because he doesn't know how to tune for speed density, so he leaves the stock programming in there. This is NOT a false accusation, it is not a joke. There are others who had the exact same situation - no fueling of the VE table. Speed desnity. IMO based on my experience, he is NOT the tuner of choice for speed density setup -- at least not via the mailorder route. He will not refund you a dime, so its not even worth bothering. His lack of communication is quite famous. Most of time he responds only when he feels threatened. This is my experience. Otherwise, its terribly slow, or typically non-existent. If it turns out to be in fact the chip in your case, I can suggest a very good tuner who will fix your problems and work with you every step of the way. From my sig, its very obvious
Contact me any time and I'll tell you more.

Oh, in case you haven't read this, check this out: http://forums.corvetteforum.com/show...47&forum_id=82 You'll see alot of dancing, glancing and irrelevant hogwash.....with the basic glaring question never being answered. There is a reason for this. It long, painful and hard to stomach after reading for awhile. There are other posts on this forum about this as well. Looking back, he charges WAY TOO MUCH for the level of work he put into the chip. Opinions of others in the know say he put almost nothing into it, maybe 15 mins. What did I get for my $250 + $10 shipping? A chip that was close to stock programming and therefore a trashed engine with a total bill you don't even want to hear about.

fnseeker

I have to hold any or all opinions on this at this time. So far there has been a few rocky things with this chip. I do not know enough to discuss this yet. How can I check if my chip is programed right. Any suggestions. I have an older Ed wright chip that was made for a stock 90 6 spd. The new chip does seem to work better than that.
On a long trip I really had to keep the rpms up on hills or my temp did rise more than I thought it should. But the temp only rose on hills. My headers were painted just before we left and they show no abnormal signs of heating. After 1000 miles still look great. Car stayed cooler during autocrossing than usual. As for the f/w it is a single steel piece from centerforce. It wieghs 30 pounds. This is 15 pounds lighter than stock. Twice the wieght of aluminum. Keep the info coming please. Mike

Nathan Plemons

Unless you have a chip reader and all the proper software there is no way to tell for sure exactly what changes have been made to your chip. What about the stock chip, how does it work?

Go under the assumption that Jesse actually did make a reasonable effort to tune your car, the chip could still be very far off from what you need. Trying to tune a car by mail, especially on a setup drastically different from what you have worked with before, is largely hit or miss, favoring miss.

Assuming the cam is installed properly and everything else is in good working order what you really need is a good dyno tune. The Hot Cam really isn't THAT aggressive, you shouldn't have the driveability problems you describe. I don't think your flywheel is too much of a problem because the Z-28 didn't have as heavy a flywheel as the vette and they still work fine.

7thvet

I dont know what you guys expect, but you shouldnt even be in 6th gear at 84 mph.
I drive an auto and Id be in third.
3.42 are ******* it down.
zoom zoom zoom.Shift that puppy.

93 ragtop

Mike, If you have a laptop computer, download a copy of datamaster. you can use it 20 times for free. Then you will need a cable to run from the aldl port on your car to the laptop. This cable can be made or purchased. Do a search in the test and tune section as to details on where to buy or make the cable.
Once you have that you can hook up to your car, drive it for about 20-45 min. recording to your laptop and then you can see what the car is doing such as timing, fuel ratios etc.
I did this and had a few of the more experienced people on this board review them for me.
As far as the programming goes on the chip you need a chip reader and a program such as CATS to read and program it. Also with this program you can read what programming has been done to your existing chip. I had Scorp 508 to read my bin files to verify what I already knew. My chip had little changes made other then the standard things like fans on at a lower temp. etc. The actual programming of the VE tables was never touched. That is why, from my own personal experience I recommend a different tuner. I worked with your tuner for close to 1 year, sending the chip back and forth 3 times, him keep telling me the problem was with my car, and the bottom line was a lack of tuning.
I am going to send you a pm message with further details. I dont want to post to much in fear of getting your thread locked.

Nathan Plemons

Do who? The gear ratios in your auto are completely different than that of a 6-spd. Technically my 92 will do 111 in 3rd gear but that doesn't mean that is the gear I cruise in. A SBC should absolutely not have to turn 3000 RPM's to sustain cruising speed. Highway cruising below 2000 RPM's is exactly why these cars get the gas mileage that they do.