2.5" Hotside turbo pipe enough for 1000rwhp?
12-04-2015, 12:14 PM
#21
Burning Brakes
Not completely true. Actually any pressure in the exhaust after the turbo equates out to 2x the pressure pre-turbo. Which is why the exhaust after the turbo is more important being larger than the exhaust pre turbo even though technically the same exhaust gasses flow through both. We've seen this many times when comparing smaller exhausts on our 3" downpipe vs a full 3" exhaust. Back pressures often become high enough that they generate enough pre-turbo pressure to blow the WG open. We see the WG's open and the power/boost taper on the high end. Simply swapping the exhaust after the turbo cures this, and the power difference is staggering.
But I also agree with the point that properly sized turbos for the application helps dramatically. From my experience most people aim too high. Twin 90mm T4 turbos to make 600whp.
CK
But I also agree with the point that properly sized turbos for the application helps dramatically. From my experience most people aim too high. Twin 90mm T4 turbos to make 600whp.
CK
-Curtis
12-04-2015, 02:30 PM
#22
Drifting
Most of the newer billet wheel turbos excel at flowing under higher pressure ratios conditions than what a typical street v8 setup would run. That is to the smaller engines advantage to make the most out of the smaller turbo and do it at higher rpm at the expense of good response down low.
12-04-2015, 04:45 PM
#23
Burning Brakes
Most of the newer billet wheel turbos excel at flowing under higher pressure ratios conditions than what a typical street v8 setup would run. That is to the smaller engines advantage to make the most out of the smaller turbo and do it at higher rpm at the expense of good response down low.
-Curtis
12-04-2015, 08:20 PM
#24
Drifting
This is true but those are physically large covers with huge exducers. 1000 ways to skin a cat, but I do agree some people oversize stuff to hit low targets and miss out on all the fun in the middle.
12-06-2015, 02:29 PM
#25
Le Mans Master
3060#
Most of the cars with smaller pipes can tolerate a bump in A/R and still achieve the same spool. IMO there is no reason to run anything bigger than 2" or 2 1/4 for anything being build sub 1500hp. Put a 2" mid pipe on a set of truck manifolds and bump the A/R.
Most of the cars with smaller pipes can tolerate a bump in A/R and still achieve the same spool. IMO there is no reason to run anything bigger than 2" or 2 1/4 for anything being build sub 1500hp. Put a 2" mid pipe on a set of truck manifolds and bump the A/R.
Last edited by Phil97SVT; 12-06-2015 at 02:32 PM.
12-07-2015, 01:25 PM
#26
Melting Slicks
I don't honestly think 2.5" or 3" will be any great advantage considering I'm planning to live between 700whp and 800whp until the tranny pops.
Your thoughts?
12-07-2015, 02:37 PM
#27
Drifting
Going larger does not decrease power, but spool. I think the point Phil and others have proven with testing over time is the smaller piping increases spool and sometimes to the point of being able to bump the A/R for better top end, while not hurting if not helping overall power output. Phil is making in the 2500 hp range and experimented with this stuff more than most of us with real world results. I'd do the 2" or 2.25" if it fits better, etc.
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MBB (12-07-2015)
12-09-2015, 08:38 AM
#28
Le Mans Master
This is my current dilemma. I haven't started mock up yet, but I'm on the fence about whether to go 2.25" or 2.5" on my S475. 2.25" piping fits the T6 flange perfectly from what I've read, and I'm going to be using stock LS7 manifolds with vbands.
I don't honestly think 2.5" or 3" will be any great advantage considering I'm planning to live between 700whp and 800whp until the tranny pops.
Your thoughts?
I don't honestly think 2.5" or 3" will be any great advantage considering I'm planning to live between 700whp and 800whp until the tranny pops.
Your thoughts?
twin 2" pipes to the turbo merged into a 2 3/4" pipe short run that runs 1" into the turbine housing.
3" pipes out of the turbo
dump the waste gates externally
cone engineering .com
2.25" would be ok but not my 1st choice
I would not use 2.5"
12-09-2015, 08:43 AM
#29
Le Mans Master
Going larger does not decrease power, but spool. I think the point Phil and others have proven with testing over time is the smaller piping increases spool and sometimes to the point of being able to bump the A/R for better top end, while not hurting if not helping overall power output. Phil is making in the 2500 hp range and experimented with this stuff more than most of us with real world results. I'd do the 2" or 2.25" if it fits better, etc.
I have plenty of data from multiple header and crossover combinations.
The best setup on my 450" was 1 7/8" headers and a 2.5" crossover.
438" was 1 3/4" headers and 2.5" crossover
12-09-2015, 10:25 AM
#31
Drifting
There was a thread on here or ls1tech where tracy(TracyRR maybe) changed his setup to what I consider is right size piping and he gained enough spool that he went up in turbine A/R and still had faster spool down low and less backpressure out the back door. It was a rear mounted single turbo corvette.
I have plenty of data from multiple header and crossover combinations.
The best setup on my 450" was 1 7/8" headers and a 2.5" crossover.
438" was 1 3/4" headers and 2.5" crossover
I have plenty of data from multiple header and crossover combinations.
The best setup on my 450" was 1 7/8" headers and a 2.5" crossover.
438" was 1 3/4" headers and 2.5" crossover
12-09-2015, 11:26 AM
#32
Le Mans Master
