LM Turbo Engine Rebuild

[turbo65]

Hey guys, first time posting but I have been lurking for a while. I think I have finally convinced the wife to break loose with the checkbook so I can work on my 180 Corsa and was looking for some opinions & insight. This topic may have been discussed somewhere else but I wasn't able to locate it.

I have done some searching and found a lot of good general info but I'm hoping to get some good detailed info/opinions.
I want to completely tear down & rebuild my engine. It's a great car and it's a lot of fun to drive but I would like to give it some more pep. I know I could squeeze more power out of it if I changed the turbo, fuel delivery, etc…but I would like to open the engine compartment and have it look more or less stock.

I was thinking of going with a complete rebuild kit from Clarks or Corvair Underground and go .030 or .040 over, dropping in a hotter cam, ignition update, maybe some head work, and….?

I was thinking the TRW pistons or possibly the KBs from Corvair Underground if there are any available still. I probably don't really need to go that "heavy duty" but I want it to be able to take anything I throw at it.
Any recommendations on cams for good streetability but more power?
Any preference on the Ignitor II vs the Crane electronic ignition in the Clarks catalog?
Anything in particular to do to the heads besides maybe a mild port & polis?
What is the consensus for roller rockers like the ones in the Clarks catalog?
What about rods, reuse the stockers or get new ones?
Anything else that I'm not thinking of?

I have thought about the big bore kits but don't know if I want go through the extra expense and I don't know if I want to tear up my block, any opinions?

Thanks!!

Steve

[Corvair.crazy]

Hey Steve, welcome to the site. I have a couple of turbo charged cars myself.

I would go with the electroninc ignition, a hotter cam, and a bigger turbo. You can get "The Turbo man" on this site to get you a compressor with more boost. You can adapt the weber carbs as well, more airflow. That is what I would do, I don't like going too crazy myself. Man if you want too you could change it up to the blow through style and really get some boost. There is my opinion.

[turbo65]

Hey Jon, thanks for the response.

I thought about going with the Weber setup but I really want to keep the stock air cleaner. Any of the Weber conversions I have seen are using big K&Ns or something. Does anyone know if there is an adaptor for the stock air cleaner for the Weber and if it will even fit?

Would I be wasting my time getting a compressor with more boost w/o changing the carb setup?

Thanks again,
Steve

[Gregory_Miller]

The carb is the restrictor to prevent too much boost (along with the exhaust system), so a bigger compressor alone wouldn't do the trick. With no wastegate and such, you are pretty restricted. Turbo man can give you more data.

[cad-kid]

Welcome Steve,

Post a pic or two of you project We love photos!

[turbo65]

I just started spending the last couple days after work tearing into it so I havn't made too much progress. I have a decent portion of the interior taken out. Here is a link to the entire album, I'm trying to document everything well.
http://s1263.photobucket.com/albums/ii631/turbo65corsa/






Unfortunatly someone thought they needed a lot of speakers or something. There were no holes in the door panels so someone must have replaced them in the past.


If you look closely here you'll notice there are no ribs on the driver side….thats because one of the previous owners, instead of fixing the cancer properly, just laid down some heavy plastic and caulked it in. The passenger side has a little rust but it isn't bad.


This is the only other part of the floor that was damaged. Someone backed over something large.

[66vairguy]

Pistons - word is the latest TRW piston quality is lacking, compared to the "old days". A forged piston is very resistant to detonation. Unless your running a computer ignition with a knock sensor you'll have to use a forged piston. Remember a forged piston requires greater cylinder clearance than stock and won't be as "quiet" as a stock piston, but the additional noise is minor.

Cams - Because the turbo overcomes the "pumping losses" of getting air into the engine you want a cam with minimal intake/exhaust overlap. Some extra lift is fine. Basically a mild cam NOT a hot one. Remember a properly set up turbo makes a lot of torque, and HP, at lower RPM. Yes drag engines are an exception, but not something you'd want to drive on the street.
Isky 260 is a good cam for a turbo, BTW Clark's 260 is NOT made by Isky.

[Mike D]

I have lots of experince with turbo cars, just not turbo corvairs.

To me, if i wanted to make power on a turbo vair, ,i would not go with a bigger turbo, but get a smaller/same size turbo that is wastegate regulated. Then add an intercooler, and larger downpipe. a setup like this will make more power, at a lower RPM, and hold it throughout the range. There is a reason every modern turbo car is done this way!

Also, carbs buy today standards do not work with boost. a well sorted EFI system, with intigrated ignition timing would be an easy extra 30hp, over a carbed setup, AT THE SAME BOOST LEVELS WITH ALL OTHER HARDWARE THE SAME To me this would be a smarter way to make power on a turbo vair, than simply bolting on a bigger turbo

Mike d