Info on 4 bolt turbos...

[BetMinesFaster]

I have read many times the power gains of 4 bolt housings, I have TA headers and recently purchased a PT70GTq, My question is, Does precision offer a 4 bolt housing that will accept my existing external WG DP, and a 4 bolt flange that could be welded in place of the 3 bolt flange on my TA's?? Sorry for the dumb post, the 4 bolts I have seen on buicks have all used the large V-band style DP's and external gates before the turbo...With the combo im building, If I could pick up some extra power by going to a 4 bolt housing that will accept my existing parts and mount in the stock location that would be worth it to me!

 

[1BADTT]

I had considered this some time ago...

If u go 4 bolt, forget about the OEM 4 bolt DP pattern. V-band is required. New exhaust housing, new dp & if u already have a THDP, u just keep losing money. Too much lost 4 the average joe to make the switch over to a 4 bolt, just my $0.02 !

 

[bison]

If u go 4 bolt, forget about the OEM 4 bolt DP pattern. V-band is required. New exhaust housing, new dp & if u already have a THDP, u just keep losing money. Too much lost 4 the average joe to make the switch over to a 4 bolt, just my $0.02 !

Thats correct. That is why i always wondered why those buying expensive aftermarket headers stayed with a 3 bolt when they gain little if anything in performance over lined up stockers. The GM engineers knew what they were doing. You gain a lot better control with an external gate and for about $900 more $ (dp and gate) you will be gaining a considerable amount of extra power potential over the 3 bolt. If you picked up 50hp for $900 more you are doing really good at that performance level imo. A used TH dp is an easy re-sale item if its not dented to hell so it wouldnt be a complete loss. Theres no need for the average Joe to 4 bolt their 11 or 12 second TR but if you plan on running 135mph or faster its definitely worth it.

 

[BetMinesFaster]

Thats correct. That is why i always wondered why those buying expensive aftermarket headers stayed with a 3 bolt when they gain little if anything in performance over lined up stockers. The GM engineers knew what they were doing. You gain a lot better control with an external gate and for about $900 more $ (dp and gate) you will be gaining a considerable amount of extra power potential over the 3 bolt. If you picked up 50hp for $900 more you are doing really good at that performance level imo. A used TH dp is an easy re-sale item if its not dented to hell so it wouldnt be a complete loss. Theres no need for the average Joe to 4 bolt their 11 or 12 second TR but if you plan on running 135mph or faster its definitely worth it.

This is just a street car, I dont want to cage it due to the invasive nature of a cage, so 135 is probabally out of the question, Just want a 9 second capable street car, and thus far I have cut no corners on doing so, if it wont cost a fortune to convert to 4 I may consider it.....

 

[boostingbuick]

I have enjoyed my 4 bolt. With the right set up it will still spool good, and make killer top end power. With my last turbo I was running high tens at 128 on pump gas, with a bad 1.84 60 footer. And that's with no cage. I just purchased a Turbonectics 72 bb s-trim. So I hope to pick up some MPH before I go for some C-16.

 

[bison]

This is just a street car, I dont want to cage it due to the invasive nature of a cage, so 135 is probabally out of the question, Just want a 9 second capable street car, and thus far I have cut no corners on doing so, if it wont cost a fortune to convert to 4 I may consider it.....

If you want to have a 9 second capable street car then you better shoot for mid to high 140's since the traction on the street wont be as good as at the strip.

 

[norbs]

And 140 mph is 800 rwhp or 1000 at the motor. SO you better build ALL your components to withstand that........