Guest Anonymous Posted September 15, 2002 Share Posted September 15, 2002 Hey all, I was just wondering if anyone here was running a SBC with a Twin turbo set-up. Just like to now what turbos you are using and how they are set up(draw through or blow through). I want to use this for daily dirving, twisty back roads/road racing, and some drag racing every once and a while(as well as smoking some of the local imports ) Quote Link to comment Share on other sites More sharing options...
DavyZ Posted September 15, 2002 Share Posted September 15, 2002 A good friend on this board and I are working on single turbo set-ups for our V8s. We did consider a dual set-up, and have not thrown that completely out the window, because you can use the 'dime-a-dozen' T3 units to make it work. After considering twin turbos, we decided that there may not be enough room unless you use VERY short headers (downward) or reverse the manifolds to point upwards, then mount them directly to the manifolds or use 90 degree elbows to mount them more forward. Choices, choices, choices. Maybe Lone will pipe in and lay a few pictures on us with his archive of twin-turbo V8s in other cars. I personally believe that a twin turbo set-up is a great way to go, but we got great deals on large single units off of ebay, that I could not resist making a purchase. You will have to figure out what engine management system and EFI you will use, and IMO, that is where the expense really lies. EFI can be 'cobbled' together, but the software cannot IMO. Hopefully some of the turbo guys (L6, V6, etc) will weigh in with some good info. Hopefully this will get you thinking and may spark a few ideas. Davy Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted September 15, 2002 Share Posted September 15, 2002 As Davy mentioned, we've researched it a bit and IMHO space wise while its not impossible to put in twins, the added plumbing and hurting the weight distribution considerably having them up front just doesn't seem worth it. Pick up the average turbo and see the weight I'm talking about. Two of those, plus piping, intercooler, wastegate etc all will be way up in front of the motor more than likely (they may sneak over the valve covers on both sides, but I think it'll be a hood clearance issue) will put all the weight distribution you saved with the chevy back up in front of the motor. Its my opinion that the best place for a turbo on a SBC on a Z car is in fact where the battery is stock. Remove the battery and put it in the back in a box. The right header (pass side) can come up towards the back in the battery area, the other banks exhaust will come under the pan easily and join the other pipe to plumb into a single turbo. The compressor plumbing then goes forward to the grill area, through the intercooler and back on the left side into the EFI's throttle body. According to most experts I've read on the subject there is no reason to run a draw thru turbo system anymore, particularly EFI, its just not necessary. You run a BOV so when you let off the gas it'll vent the boost pressure to atmosphere instead of trying to stop the turbo's progress. Before you say, well yeah but a single turbo will be laggy and won't give enough boost. Consider the torque difference on the V8, the area of non boost will still have much more torque due to displacement. Displacement also doesn't require as much boost to get power as what you read about the 4 and 6 banger guys using. Running 12 pounds of boost on a 350 will get you nearly 600 hp at only 6000 rpm's, if its built to rev to 7k it'll make nearly 700. Thats well within the range of a single turbo application. Heres a calculator to play with: http://www.turbofast.com.au/tfcalc.html Anyway, got long winded as always, but that is just my opinion, I'm sure twins could be done, but I just don't see the need in a car as light as the Z, if 5-700 hp doesn't get you where you want to be, then your looking for way more excitement than I'd want to have in a Z car and without serious tubbing of the car and slicks its all just number anyway as you won't find rubber to hold that much HP particularly on the street. Good luck with whatever you decide. Regards, Lone Quote Link to comment Share on other sites More sharing options...
biohzrd Posted September 16, 2002 Share Posted September 16, 2002 i have also wanted to do a turbo v8. i was really wanting to do a twin turbo setup and was wondering about the diffs b/t the t03 and t04. i've always heard that to3's would run out of air flow at about 5500 to 6000 rpm and that the to4's would be the better choise b/c they would flow all the way up to 7000+ rpm. also what about using a deisel turbo. they seem to be pretty large but can they handle the rpm's of a gas powered v8 Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted September 16, 2002 Share Posted September 16, 2002 I'll let you know if I ever get mine hooked up. I have a older holset I was given by a great friend. Its off a 360" cummins six cylinder diesel and should work out rather well, they run nearly 20 lbs of boost, I won't be running near that (unless I get a pile of cash to put in forged everything ). Other potential candidates, powerstroke diesel turbo's and GM Diesel turbo's, any of these for realitively sane boost levels should surfice and are available fairly reasonable on Ebay some of them new in the box even. I'm not sure RPM wise, true the diesels are much lower speed, but then again I'm not looking to spin the motor much over 5500 and trying to build good mid-range which it should work rather well at. Regards, Lone Quote Link to comment Share on other sites More sharing options...
DavyZ Posted September 16, 2002 Share Posted September 16, 2002 Originally posted by biohzrd:i have also wanted to do a turbo v8...I was wondering about the diffs b/t the t03 and t04... that to3's would run out of air flow at about 5500 to 6000 rpm and that the to4's would be the better choise b/c they would flow all the way up to 7000+ rpm.... In a V8, you really don't need the motor to spin so high. Although the sound of a V8 tacking out at 7000 rpm may be sexy, getting the package built to stay together is so much more expensive then say, one that only needs to spin to 5500 or 6000 rpm. The V8 makes great torque anyway, so even a 8:1 compression will work just fine getting the tires planted...until the boost comes on...then BAM! You kick it up a notch and you are gone, man, totally gone! The idea is totally consuming and I cannot wait for the day I'll have this up and running. Davy Quote Link to comment Share on other sites More sharing options...
biohzrd Posted September 16, 2002 Share Posted September 16, 2002 i guess i should let you know what i'm building. it's going to be a 406 destroked to 377. 8 to 1 comp. with a converted lt1 intake and pro action heads. i want 700 to 800 hp. would twin to3's be able to handle it or am i going to have to use something bigger. to kill some of the torque it's going to have to have a higher rpm cam so to speak. thats my delima. any help is appreciated Quote Link to comment Share on other sites More sharing options...
Guest BigE Posted September 16, 2002 Share Posted September 16, 2002 Here's a kid who did a twin turbo setup on a TPI 350 Camaro. Different car, similar motor. http://www.skulte.com/turbo.html Quote Link to comment Share on other sites More sharing options...
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