Due to some seemingly unfixable electrical gremlins including no signal from sensors, a wire harness that burned off when it came in contact with a header and what appears to be a bad ECM, now my tuner is telling me that my 230/236 110lsa cam (that he had approved as the upper limits of the factory ECMs abilty before I purchased and installed it) is untunable with a speed density system.I am considering what would probably be a very unpopular option with the larger Corvette crowd, but please reserve your judgement or PM me with your disapproval.
Basically, I am at my wits end.
I think I might do a Carb conversion to the 91'. All of the problems that I have are computer related. The car was a basket case when I got it. It is FAR from stock including a full 6 point cage, custom seats, new engine and so on. I am not going to "chop up" a nice original by any means.

Here is what I think has to happen:

1. Convert the fuel supply to a low pressure system
2. Install standard intake manifold and carb/air cleaner
3. Clearance the hood (until $$$ for hi-rise hood)
4. The car already has a MSD 6Al ignition system
5. There is a converter made that allows the ZF to be run and feed the factory speedo without running through the computer

What else am I missing?

 

I am sure that most people here are going to tell you that the electrical system is not "unfixable", we seem to have quite a few purist here.
With that said, I think you are on the right track. If you stay with a low profile intake, you should not have to clearance the hood any.
I have my 84 converted to a carb.

Come to think of it...I still have the first intake (I'm running a High Rise now) and a quadrajet sitting in the garage. This could save you a few bucks.

 

:bump:

 

You will need to make some adaptors for the linkage to the carb.


PM Sent

 

ugh... going to carbs... that is the most bass-ackwards thinking. I don't agree with it.

And it has nothing to do with being a "purist" it has everything to do with building the right engine.

The car was a mess, fine, but there are ways to repair this. First off, I am curious why the tuner can't tune it. That bothers me. The 91 ECM is pretty good. I know it's SD, but it could be converted over to MAF, so that's not a problem.

Also, harnesses are not that expensive. I would call Contemporary Corvette, Corvette Salvage (Dino's) or Painless and see what they have.

The other option is to do a FAST system, which might be your best bet.

Unlike Rich's 84, where upgrading to a carb is a good idea, I am not so sure with later injection systems.

Carbs are not as tunable as you think. They are analog devices that work great within a power band, but that's about it. EFI is so much more linear and is capable of dealing with altitude differences much easier. It is intellegent.

Then again, you would loose much of the dash board, and the ABS might just barf. The later electronics are much more integrated, the CCM is expecting a signal so it can communicate with the EBCM... this just gets ugly.

To me, it would be easier to update the injection, fix or replace the harness and be done with it.

 

Lower the water instead of building a higher bridge - switch to MAF, not SD.

 

Tell the people in New Orleans that.

 

I am a proponent of the FAST route. I have two systems and would consider this on any vette that I would own, provided that it is installed propoerly.

Aaron

 

ttt

 

As with all things it depends on how you use it.If your going for a drag car it may be a good alternative but your fuel milage off the track will suffer.I tend to agree with Bogus although that is a hefty cam.I would think bigger injectors might be needed but mabey you should talk to Alvin about the tuning issue.He does wonders with SD cars.

 

Here is what I think has to happen:

1. Convert the fuel supply to a low pressure system
2. Install standard intake manifold and carb/air cleaner
3. Clearance the hood (until $$$ for hi-rise hood)
4. The car already has a MSD 6Al ignition system
5. There is a converter made that allows the ZF to be run and feed the factory speedo without running through the computer

What else am I missing?[/QUOTE]


Do what makes YOU feel good. I wont do it because I am facinated with what makes my car tick, but I can see your frustration. You will need a distributor with an advance mechanism. I prefer mechanical and no vaccuum. The carb conversion will not be cheap. A good carb with fuel lines and a regulator will be $400-500. Plus the intake, distributor, and fuel pump. You can spend $1000 to do it right, but it will make good power if you choose the right parts.
GOOD LUCK

 

You would not need to convert to the low pressure fuel system if you use a return style regulator. I ran a Mallory for a long time with no problems. I hear you with your frustrations; I had a similar experience with an 88 that is now a race car. In an ideal world with unlimited funds and time the FAST systems are great but a huge problem is the time involved to do the job right and making it look professional. Most people simply get tired of working on the cars and a lot of good vette people sell out for something less intensive. Go the route you want, you don't need our approval. If you want some specifics I can give you all you need to do the job since I have done a few, just PM me. Good luck with your decision, let us know how you turn out and if you are happy! If it where me I would consider the FAST system but realize the higher costs and possible issues that there may be with both possibilities before I did anything, but I will run a carb 9 out of 10 times.

 

If the wiring harness as a whole is that fried and you like that cam, throw a double pumper on it and call it a day. Yes, when everything is right with FI its great, but that much cam timing with a 110 lobe isnt going to like the MAP. If thats what you wanna do, go for it. I personally wish these cars didnt need all the electronics they have to run.

 

I really appreciate all the input guys!

This car gets driven about 1000 miles a year, tops. I have two young kids at home and as well know, its not really a family freindly car...

My time with the vette has been very good so far. I bought it for a song from a guy just as Deakins described, he ran out of energy and walked away from it. With the previous electrical issues I have had with the car, along with the impending financial doom of getting this all worked out, I am starting to feel my interest slipping away from it.

I do not know anything about the computer system of this car, nor do I think I want to know. As I look through my pile of car magazines every month, I see muscle car after muscle car with simple high horsepower v8's, modern brakes and suspension upgrades to make them ride like the Vettes we are already driving everyday. The hot thing right now is power, brakes and handling - just what a C4 is all about.

I am not discounting the arguments over tunabilty, gas mileage, optimum efficiency and so on. All extremely valid and worthwhile points!
I just think for my particular car, in my particular siutation, I would rather have something under the hood that I am comfortable working on. I do not have the knowledge of some to diagnose these gremlins or the funds of others to send it to a qulified tuner every time it hiccups.

Please keep your thoughts coming, I think has the potential t shake a few more out of the woodwork who might have considered the project.

Again, Thanks to all who chimed in!

 

Your Welcome.

 

Dont give up on the car, if you get burned, put it aside for awhile. Ive had one apart for over 5 years and it has cost unbelieveable amounts of money, sacrifice, etc.http://forums.corvetteforum.com/show...45&forum_id=26 Been burned out on it for years due to being ripped off from shops, no place to work on it, S/O leaving me over it, etc.
Dont become another ad in the paper selling it off, you'll regret it. Get it the way you want, then if you dont like it get rid of it. You buy another car youll have headaches with it too, just different ones. Trust me, I know-Ive had all my cars up for sale recently at some point due to financial burnout, just gotta keep at it.

 

If I choose to go that route, I am going to have a really nice SuperRam upper and lower, BBK twin 58mm TB, Fuel rail and Accel 24# injectors for sale to help finance the conversion

 

Sounds familiar!

As you know, i made the decision to go carbed. i am at the end of my financial rope, and am going to be ahead possibly $4k by doing so. Mine, like yours, is not a DD, and will only be used on nice weekends. I've put too much time, energy, angst, humiliating mistakes, etc, into this, and im not throwing away any more good money after bad. My car has been on the jackstands for 15 of the 18 months that i have owned it. In essence, my 90 L98 is an old car, a toy for me, and i want to play, not pay.

I don't need to see Dr. Phil either. I just want to see the road.

 

padrummer1 does this mean you don't need the valve covers after all? Did you get them as promised? I can see where you have bigger things on your mind but I was wondering if you got them okay. FWIW I would try and stay with electronic injection, I can't offer any help but I know somebody here can. Sorry to hear your having so much trouble.

 

After seeing those things, I am using them! They are beautiful! I will sell the fabbed ones