Has anyone attempted rear mounted turbos?
12-12-2016, 11:05 AM
#22
I've ridden in a couple of these STS cars over the years and I'll say for a fun street car...they run very well. They run small turbos that spool quickly. The size of the pipe is critical....but seems to work well overall. Is it the ultimate power adder? No.....but it is very effective. One thing you have to be aware of is scavenging the oil with a pump usually and pumping it back to the engine or to a tank/cooler etc.
I was able to mount twins in the "gill" area of my '67 without too much drama...certainly a C-3 could be done the same way.
JIM
I was able to mount twins in the "gill" area of my '67 without too much drama...certainly a C-3 could be done the same way.
JIM
12-12-2016, 12:22 PM
#23
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I used Borg Warner EFR series turbos. They have integral wastegates and blow-off valves...so a lot less plumbing and hassle. I built brackets to attach them to the frame and then hooked them to a set of McJack's shorty headers from Corvette Central. CX Racing has all the plumbing bits you need at great prices.
I didn't use an intercooler...I just used a Snow Performance water/meth kit and it does fine.
I fabbed up my intake using an 8-71 blower manifold, but really didn't need to. I just don't like the aesthetics of the elbow's on a stock intake..but it would certainly work at least as well.
One pic is during the fab stages when I still had a carb mounted to the EFI intake for testing...but you can see placement.
Winter plans include re-doing the plumbing to run between valve covers and firewall. I hate having anything go over valve covers, but I did it that way in respect of time constraints.
Haven't had it to drag strip yet, but I did run 177 MPH in the 1/2 mile with boost turned down to 10 psi and some pretty serious traction issues.
It made 1140 RWHP on 91 octane (about 18 psi).
It's a blast on the street. Turbo's "light off" about 2500 RPM!
Here's a dyno video:
View My Video
JIM
Last edited by 427Hotrod; 12-12-2016 at 12:30 PM.
12-12-2016, 12:41 PM
#24
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I also went a little overboard with the ignition system. I have Holley EFI and use their DIS ignition system.
Again, in the interest of aesthetics, I "hid" the 4 coils inside the car under the dash on the trans tunnel. I used 8 "passthrough" connectors from MSD and ran short plug wires from coils to the inside terminal on passthroughs and then another set of wires on firewall side so I could run the plug wires easily up from underneath. I had DUI (Davis Unified Ignition) make the plug wires to custom lengths for me- plug and play.
I used an MSD oil pump drive to replace the distributor and use the crank trigger to control the EFI/Coils. Again, not necessary...but I liked the clean look.
It's been running this way for a couple of years now and all works great.
JIM
Again, in the interest of aesthetics, I "hid" the 4 coils inside the car under the dash on the trans tunnel. I used 8 "passthrough" connectors from MSD and ran short plug wires from coils to the inside terminal on passthroughs and then another set of wires on firewall side so I could run the plug wires easily up from underneath. I had DUI (Davis Unified Ignition) make the plug wires to custom lengths for me- plug and play.
I used an MSD oil pump drive to replace the distributor and use the crank trigger to control the EFI/Coils. Again, not necessary...but I liked the clean look.
It's been running this way for a couple of years now and all works great.
JIM
Last edited by 427Hotrod; 12-12-2016 at 12:42 PM.
12-17-2016, 01:25 AM
#28
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Well I know someone locally that does the full install. He does mostly camaro's (4th & 5th gen) but I'm sure he'd do any car. He claims the 350" motors get to the 600hp range. This is single turbo. Entire exh pipe gets heat wrapped. I'm not going to get into the theory here as the long run back to the rear mounted turbo has me wondering what the power band looks like. But theory is one thing any results are another.
My comparison is to the roots superchargers that are even street legal and can get a 350" close to the 500hp range. BBC w/roots non-EGR blower and 1000hp is possible. Yes you will need a new hood but I don't see that as a big deal. But who the heck needs 1000hp on thier street machine anyways?
Roots blower can be very street friendly and makes power from idle to max RPM. $2200 for entry level Wieand kit.
I just wish they sold one for a 4th gen Camaro w/Gen II sbc. No manifolds for this and not enough hood/cowl clearance. That's why I read of so many rear turbo or straight out turbo conversions on 4th gens.
To answer one question for the OP is most power adder vendors say 'bout 10psi boost is good'nuf for the street driven cars.
My comparison is to the roots superchargers that are even street legal and can get a 350" close to the 500hp range. BBC w/roots non-EGR blower and 1000hp is possible. Yes you will need a new hood but I don't see that as a big deal. But who the heck needs 1000hp on thier street machine anyways?
Roots blower can be very street friendly and makes power from idle to max RPM. $2200 for entry level Wieand kit.
I just wish they sold one for a 4th gen Camaro w/Gen II sbc. No manifolds for this and not enough hood/cowl clearance. That's why I read of so many rear turbo or straight out turbo conversions on 4th gens.
To answer one question for the OP is most power adder vendors say 'bout 10psi boost is good'nuf for the street driven cars.