New motor for my vette...

Originally Posted by Rich Z

Yes, as this will be part of the tuning process itself, and is a real good way to tell if you have everything tuned to optimum settings. I told him that peak horsepower isn't as important to me as acceleration and throttle response. More "seat of the pants" kind of thing more than bragging rights numbers. So I would much rather sacrifice a higher peak number to gain better low to mid range power, where you tend to be most of the time driving on the street. In some respects I think I would probably have liked a supercharger more so than the turbo chargers, but there were too many drawbacks with the superchargers that were available then. I got rear mounted turbos to help with weight distribution and to keep all that heat turbos generate out of the engine compartment. Plus there is no belt to throw with the turbos, and they just seem to be a sensible choice, as they use waste exhaust gases to operate instead of inflicting parasitic losses on the motor to make them work. Like anything else, there were compromises that needed to be picked from based on personal tastes.

Right now my vette puts down 529 rwhp and 514 rwtq, that you would think would be plenty for me. And actually it is. Quite frankly, the additional power is just icing to the cake for me. The new engine just happens to provide a lot more power, and it also allows me to remove the 6.5 psi restriction now in place on the max boost going to the engine. With all forged components and 6 bolts per cylinder for the heads, I can open this up as high as the turbos are able to go.

Of course, my tuner has already told me that he is going to set the rev limiter to 3500 rpm during the break-in procedure....

Are you getting a new intercooler for your turbo's? I'd imagine those turbos would get a heck of a lot hotter at full boost as opposed to 6.5 psi.. but I'm not really familiar with corvette engines.. my 1.8t GTI stock put out about 9psi.. but i got it chipped and now it peaks at 20 and usually holds at 17 psi and any more than that and i'd need a bigger intercooler. But im guessing that your vette had a pretty large one for those twin turbos..

Haha If i had that car with the new engine i'd be way too tempted to rev that thing all the way up to redline before break in! Its probably best he's setting the rev limiter haha

Originally Posted by mynamesrick

Are you getting a new intercooler for your turbo's? I'd imagine those turbos would get a heck of a lot hotter at full boost as opposed to 6.5 psi.. but I'm not really familiar with corvette engines.. my 1.8t GTI stock put out about 9psi.. but i got it chipped and now it peaks at 20 and usually holds at 17 psi and any more than that and i'd need a bigger intercooler. But im guessing that your vette had a pretty large one for those twin turbos..

Haha If i had that car with the new engine i'd be way too tempted to rev that thing all the way up to redline before break in! Its probably best he's setting the rev limiter haha

Charge cooler... Get a spare A/C unit and cool it even more........

Originally Posted by mynamesrick

Are you getting a new intercooler for your turbo's? I'd imagine those turbos would get a heck of a lot hotter at full boost as opposed to 6.5 psi.. but I'm not really familiar with corvette engines.. my 1.8t GTI stock put out about 9psi.. but i got it chipped and now it peaks at 20 and usually holds at 17 psi and any more than that and i'd need a bigger intercooler. But im guessing that your vette had a pretty large one for those twin turbos..

Haha If i had that car with the new engine i'd be way too tempted to rev that thing all the way up to redline before break in! Its probably best he's setting the rev limiter haha

Actually one of the beauties of the STS rear mounted turbos is that the air charge doesn't have to be cooled down that much just prior to going into the throttle body. I'm sure you've seen pics of underhood turbos glowing red hot, which you pretty much need to expect when they are so close to the exhaust ports on the heads. But of course, there are pros and cons to the rear mounted turbos as well just from the distance the air charge travels.

Some are even saying that I may need bigger turbos (perhaps even ones with ball bearings instead of the standard journal style bearings) to take full advantage of the increased air flow through the new motor. I'm really not all that concerned about that right now. Of course, if my current turbos give up the ghost, then that would be the time to consider an upgrade anyway.

Originally Posted by Rich Z

Actually one of the beauties of the STS rear mounted turbos is that the air charge doesn't have to be cooled down that much just prior to going into the throttle body. I'm sure you've seen pics of underhood turbos glowing red hot, which you pretty much need to expect when they are so close to the exhaust ports on the heads. But of course, there are pros and cons to the rear mounted turbos as well just from the distance the air charge travels.

Some are even saying that I may need bigger turbos (perhaps even ones with ball bearings instead of the standard journal style bearings) to take full advantage of the increased air flow through the new motor. I'm really not all that concerned about that right now. Of course, if my current turbos give up the ghost, then that would be the time to consider an upgrade anyway.

only one word comes to mind there. garrett. get some gt30 or 35rs. best turbos ever in my mind. im not a fan of remote mount turbos and even though everyone says that you need no intercooler to cool it, well you dont, its not hot as it would be on a normal set up, but also, if you have a front mount, or even a top mount on a normal in bay turbo set up. and put a meth kit on the cooling cycle of boost, nothing can beat that. my last car, a 91 civic hatch was only running 7 psi off a jackson racing blower. it was my first blown car and it was quite different than snails in other cars. no boost lag and it was nice.

Originally Posted by pwargcm

only one word comes to mind there. garrett. get some gt30 or 35rs. best turbos ever in my mind. im not a fan of remote mount turbos and even though everyone says that you need no intercooler to cool it, well you dont, its not hot as it would be on a normal set up, but also, if you have a front mount, or even a top mount on a normal in bay turbo set up. and put a meth kit on the cooling cycle of boost, nothing can beat that. my last car, a 91 civic hatch was only running 7 psi off a jackson racing blower. it was my first blown car and it was quite different than snails in other cars. no boost lag and it was nice.

Heck, I have no idea what model turbos I have in my car. Probably in the manual some where, but the chances of my finding that thing any time in the next decade are VERY slim.

Now the STS does have an intercooler but the air charge coming from the turbos isn't all that hot. Just being mounted in the back makes something like an 800 degree temperature difference in the turbos. So that's a lot of heat that doesn't get transferred to the incoming air charge. Also a huge reduction in heat that the oil is exposed to and pumped back to the crankcase.

You know I've heard people complaining about "lag" in the rear mounted turbos, but really, I don't notice anything that seems like a problem. Far from it, actually. Punching it in third gear is pretty much like being in a jet plane during takeoff. It just pushes you back into your seat, and you just HANG ON to the steering wheel!

There is already air in the inlet pipes and the intercooler, so it's not like the push of air when the turbos really start singing is dumping into a vacuum that has to fill up before the air charge gets into the throttle body. So it may be a softer transition then turbos up close and personal under the hood, but not all that much. And quite honestly, even this so-called "gentle" push can take you by surprise. A harder and more sudden push with that much "oomph" behind it (200+ additional horsepower with just 6.5 pounds of boost), can be enough to break things, or spin the wheels when you really don't want it to. Plus my headers are three inch collectors necked down to 2.5 inch inlet pipes for the turbos, so this in itself will accelerate the exhaust going into the turbos to help them spool up faster. I've had people tell me that headers aren't needed nor wanted with turbos, but I believe in a rear mounted system, they are VERY beneficial.

Heck even at fourth gear coming off of an on ramp on an interstate, I can keep my foot steady on the gas pedal and feel the power building in the motor and the speed increasing proportionally without having to press any further on the pedal. Very cool effect...

Originally Posted by Rich Z

...Then I'm going to have that older engine put into Connie's pickup truck... She'll be about the only person around with a vette powered pickup truck, I would imagine...

You could always throw the old turbos on the wife's truck with the old motor. Make it an even bigger surprise for someone not expecting it.

Wednesday the drivetrain was extracted from the frame/body of my car. Pretty interesting watching the separation take place....



Chris discovered that one of my turbos has developed a seal problem and was leaking oil into the intake part of the turbo. So he's going to be sending them both back to STS to be rebuilt. But at least this was discovered before it developed into a more serious problem that could have destroyed the turbo.

Yesterday (Thursday) the guys got a late start, but the torque tube was separated from the transmission/differential, and then both the front and read cradles were taken outside to be cleaned up.

I believe today some of the new stuff is going to be assembled. I think at least the new carbon fiber driveshaft will be installed into the torque tube, and maybe more stuff will start to be put into place in the drivetrain. So it should be exciting to see this all coming together....

Thats pretty cool. I didn't know they could do that. How long do they think before it's all back together?

That is really interesting Rich. I've never seen that done.

Originally Posted by tstephe3

Thats pretty cool. I didn't know they could do that. How long do they think before it's all back together?

I'm not exactly sure. Wednesday we found that one of my turbos has a bad seal, so we are sending them both back to the manufacturer to be rebuilt. Then today we found that the torque tube (that's what actually holds the driveshaft - that long aluminum tube in the video) has a bearing going bad, so I'm going to replace both of them while the guts are laying all over the floor. No telling what else might show up, but I figure that this is the time to fix anything that needs fixing or replacing. I've got over 90K miles on the car, so many of the wear items are getting worn by now. Also replacing all the rubber bushings in the suspension as well. These all take time to do. But better now then another 10K miles down the road and have to pay to have things pulled apart again after being towed to the shop.

I really don't like being without my car now that I have a bit more free time to be driving, but them's the breaks, I guess....