Turbocharged street cars/motors

[srt]

Your experiences? High, quick building boost? Waste gates?

I have experience with smaller (2 liter) water cooled stuff from the early 70s but am wondering what's been done with corvairs.

Driveability. Heat control. Etc.

What have you done, used & found to have been reliable for street use with an occasional weekend freeway cruise?

Sent from my LGLS885 using Corvair Forum mobile app

[acarlson]

I've been working my my '65 turbo Corsa 4 speed for about 2 years now. I've completely torn the engine down, split the case, had the crank reground and installed all new forged pistons, full fin cylinders, rings, bearings and seals. Rebuilt the carb and turbo using Clark's rebuild kits. My engine is basically stock - I did not install oversize pistons. I did have the heads machined so I am running a higher cylinder compression then a stock turbo engine. My turbo engine, transmission and differential are out of a '66 Corsa so they are not original to the car.

Some additions I did during my rebuild:

I installed an Innovate Wideband O2 sensor and gauge which makes adjusting the carb easy and monitoring the rich/lean conditions while driving possible.

I installed a Dakota Digital CHT sensor and gauge. I found that the stock CHT gauge was very slow to respond to head temperature changes while driving. The stock gauge might barely move while the DD gauge could show 30 degree swing in temps.

I installed a VDO vacuum/boost gauge. I found that the stock gauge would indicate vacuum just fine but would not register boost from the turbo.

I found that above 2000 RPM the CHT temps would rise quickly and at 3K RPM with some boost they could exceed 440 degrees. That was too high to my liking so I installed a Snow Performance Stage 2 Methanol Injection kit. I'mm running a 50/50 mix of denatured alcohol and distilled water. This seems to keep my head temps down under boost although I only have a 100 miles or so on the injection system so we'll see how it does over time.

The stock turbo is not real quick to spool up and it max's out at about 8 psi. You can make additional mods to the turbo to get more boost out of it but you would have to add a wastegate to control the boost. I have not done that. The engine work I've done is to make a dependable driver not to try to beat another car to the next stoplight.

Alec

[thewolfe]

The stock turbo is easily capable of well over 8psi boost. It's the dinky yh carb that limits boost the most. I run a quadrajet with a modified turbo - it has the larger e flow compressor and rajay housing. I get full boost - 17psi in first gear. On hot days I run 10 psi and when temps are below 80 or so I go 17-18psi. Of course a waste gate is necessary and I have electronic boost control, water/meth injection, safeguard timing control, modified 95hp heads that are ported, oversize valves, deep seats, ceramic coated chambers and valves, 140 exhaust tubes and manifolds with a custom made crossover pipe that is alarger diameter to match the 140 logs. All exhaust is ceramic coated, crossover and up pipes wrapped and turbo blanket to keep heat in. The block in my car was rebuilt before I purchased the car. It has keith black pistons which have taken quite a beating over the years but still runs great! I'm not sure exactly what my head temps are because I use the stock thermistor with the adapter from Clarks so it can be installed in the 95 head. Problem with that is the sensor no longer goes all the way into the head so the reading never goes much past 350 but I know it gets hotter than that. When I had stock heads it would run about 400 cruising on the freeway. The new vairtrix head sensor is on my list to purchase. I have no problems cruising at 70 all day long in the summer or romping on it often, within reason. Climbing mountains at full boost for extended periods would likely overheat the heads but that's not a situation I ever deal with so it isn't an issue for me.

[66vairguy]

srt - some good responses, but note head temperatures are one concern. Corvair engineer Benzinger responded to questions at a Corvair convention many years ago. One of the questions he answered was about "inadequate" Corvair cooling for the stock turbo engines. Just off the top of my head Benzinger responded that yes at WOT throttle the heads would overheat after about a minute, BUT the Corvair would have reached top speed before then and sustaining that speed would be illegal. So basically WOT operation to accelerate to legal speeds or for passing was NOT an issue. Note that Benzinger did not address the issue of extended boost times going up a steep incline or in competition.

Some now use water injection at the fan inlet to enhance cooling for extended boost operation. The stock Corvair system had limitations, but it was simple and reliable.

Today there are modern turbo's with integral wastegates, electronic ignition, fuel injection, ox sensors, all coordinated by computer to enhance the Corvair performance - $$$$$ of course.

You might look at the history of the 62 Oldsmobile F-85 JetFire turbo with the aluminum V8 (latter sold to the Rover group). Unlike the Corvair turbo the Olds turbo had a relatively high compression engine with quick response boost limited to a modest pressure with a wastegate. It was decades ahead of it's time, but was a failure mostly due to complexity. No computers then, just relays and vacuum/pressure controls. It was beyond the ability of the average dealer mechanic to diagnose and repair. There was also a water alcohol reservoir for injection during boost and if the owner didn't fill it with a "dealer only" solution a switch would cause the wastegate to limit boost. It was reported that some turbo's that would carbon up and stop working. Due to customer complaints a lot of the turbo engines had the systems removed and a four barrel carburetor and new intake manifold installed.

[63Turbo]

The main reason that the turbo's run so hot at highway speeds is timing!!! it cant be said enough. Any of the NA corvairs would be running way hot if they had the same distributor and timing. It is the lack of vacuum advance that does that.
There' seriously almost 100 degrees difference in head temps between running 24 degrees at 3000-3500 rpm and 42 to
44 (like mine does)… my timing has vacuum advance, rpm advance and boost retard and has been run both with a couple
different carburetors and more recently with port fuel injection. Head temps with a more or less stock set-up could get
to 400, under the same load with strong vacuum advance it's 300 to 320.
Yes the stock cooling system is a problem (and there is a real fix coming!) but it is an excuse to blame it all on the fan.
A better timing curve for turbo's really goes a long way to help them run cooler

[Flagon_15T]

I'd like to rebuild my grandfather's Corvair with a turbo engine, but it won't happen before a couple years at least (due to my job, I work 10 month abroad/6 months from home) and I'm a little bit afraid that the car would end up being difficult and expensive to maintain. The thing is that I've been working a lot on themes like this, the generalisation of self driving cars and their impacts on markets such as real estate, travel, retail and public transportation, and I just hope that I don't end up with a dinosaur from a bygone era when my project will be finished. Of course, I'm not against owning a collection car, and I don't think that the change will be quick to reach rural Kansas, but I still worry a little about future regulations and laws regarding non-self driving cars. It may be because I've spent too much time in Europe, but I can't get this thought out of my head when I plan for the future of my Corvair...

['stitch']

Rebuild it! It will put a 'Smile' on your face, (And others when they see you). Live for today and tomorrow will take care of itself. Worrying about what the future will bring, is like sitting in a rocking chair.... It'll give you something to do, but you won't get anywhere. And they are neither 'Difficult' or 'Expensive' to maintain. Don't stress it. Stress is an ager. Do what makes you makes you 'Smile'!

[SyntheticBlnkerFluid]

DSCN1633.JPG

The main reason that the turbo's run so hot at highway speeds is timing!!! it cant be said enough. Any of the NA corvairs would be running way hot if they had the same distributor and timing. It is the lack of vacuum advance that does that.
There' seriously almost 100 degrees difference in head temps between running 24 degrees at 3000-3500 rpm and 42 to
44 (like mine does)… my timing has vacuum advance, rpm advance and boost retard and has been run both with a couple
different carburetors and more recently with port fuel injection. Head temps with a more or less stock set-up could get
to 400, under the same load with strong vacuum advance it's 300 to 320.
Yes the stock cooling system is a problem (and there is a real fix coming!) but it is an excuse to blame it all on the fan.
A better timing curve for turbo's really goes a long way to help them run cooler

Is that fan a product you’re making? It’s the first time I’ve seen anything like that.

[azdave]

Is that fan a product you’re making? It’s the first time I’ve seen anything like that.

An eight page thread is here.
http://corvaircenter.com/phorum/read.ph ... 610,page=1

[SyntheticBlnkerFluid]

Is that fan a product you’re making? It’s the first time I’ve seen anything like that.

An eight page thread is here.
http://corvaircenter.com/phorum/read.ph ... 610,page=1

Thanks, I don’t go to Corvair Center anymore, so I never saw it.