Borgwarner Twin Scroll 7670 With Dyno Graph
For some comparison the "old" setup was a BR 2Liter with the HKS 280s regularly run to 9600 RPM for road racing. This setup was out of my old Silver car which won more events placed second in the ones it didn't win and set and held more Evo Road Course track records than any other evo I have owned. It was used to get good out of the corner drive with enough RPM range to minimize shifting to 5th on our tracks. This new setup defines a different league...lol. Shift at 6800 peak HP and you are at 5800 for your next LUNGE...or go to the 9K redline and save a shift when the chance presents itself...just like my old Buschur Racing WINNING setup But on STEROIDS and a hit of CRACK for spice. ;-)
Just to get the topic at hand out of the way, man, that is some sweet power. Nice work. That's 1 for the EFR so far, can't wait to see more.
What turbo use to be on it in that comparison? That's a crazy improvement in powerband.
To address some misinformation:
Right thought process, wrong reason. Stainless steel has a lower thermal conductivity then normal steel or cast iron.
Thermal Conductivity [W/m-K]
1020 Mild Steel - 52
Gray Cast Iron - 30
304 Stainless - 21.5
321 Stainless - 16
Ni-resist - 13-40 (varies)
Inconel 625 - 9.8
Titanium 6AL-4V - 6.7
Reason tubular manifolds put off so much heat has more to do with surface area and material thickness. A cast stainless manifold with equal surface area and thickness as a given cast iron manifold would reduce engine bay temperature. Except compared to Ni-Resist cast iron; but Ni-Resist is a high nickel cast iron. Kind of like how Austenitic stainless steel has a lot of nickel in it too.
If you want a solid reason to shy away from tubular manifolds, go for cracking. But even then, if the welds are good, there is little to worry about. The few manifolds I've build have had 0 problems.
As for losing 10% power, there is an easy fix. Pull intake air for the turbo inlet off the front of the car, sealed off from engine heat. Done. Car feels like it does on a cold morning all the time.
What turbo use to be on it in that comparison? That's a crazy improvement in powerband.
To address some misinformation:
Stainless steel sheds heat very quickly. any welder can tell you that. stainless cools to touch much faster that any other metals. This is a problem for turbo use as that quickly shed heat ends up in your engine compartment. The first tubular car I drove shocked me the first time I lifted the hood after hard drive. I was blasted with hot air in the face like I never felt before. Shortly there after spoke on the phone with a guy in NY who measured his engine compartment temps. (eclipse not evo, doesnt have good hood vent like evo) He found max of 175 with factory cast manifold and the temp jumped to 325 with a tubular manifold. If anyone ever notices how fast your car is when its cold. Then when fully warm you loose 10% or more power this would be why.
Thermal Conductivity [W/m-K]
1020 Mild Steel - 52
Gray Cast Iron - 30
304 Stainless - 21.5
321 Stainless - 16
Ni-resist - 13-40 (varies)
Inconel 625 - 9.8
Titanium 6AL-4V - 6.7
Reason tubular manifolds put off so much heat has more to do with surface area and material thickness. A cast stainless manifold with equal surface area and thickness as a given cast iron manifold would reduce engine bay temperature. Except compared to Ni-Resist cast iron; but Ni-Resist is a high nickel cast iron. Kind of like how Austenitic stainless steel has a lot of nickel in it too.
If you want a solid reason to shy away from tubular manifolds, go for cracking. But even then, if the welds are good, there is little to worry about. The few manifolds I've build have had 0 problems.
As for losing 10% power, there is an easy fix. Pull intake air for the turbo inlet off the front of the car, sealed off from engine heat. Done. Car feels like it does on a cold morning all the time.
Last edited by 03whitegsr; Sep 8, 2011 at 08:25 PM.
yeah 10" enkei's with the 295 toyo R888....about as wide as a "normal" 305..all under the stock Sheet metal quarter panels....(with the robispec tubular chromoly lower control arms for inside clearance.)...
03whitegsr, thanks for your technical correction. although I have no idea what you actually corrected. you are wonderful with theories. I will stick to my practical application. Everything I said is 100% true. stainless manifolds expel more heat into the engine compartment than factory cast manifolds. period. that heat heats up everything IN the engine compartment reducing the ability of engine to make power. I run cold air intakes on all my setups so that is not the solution to adding heat to everything metal in the compartment. If your theories say that it shouldnt happen then its your job to figure out why. I could really care less.
Evolving Member
Joined: Aug 2011
Posts: 210
Likes: 0
From: Earth
Thanks!
thanks for the reply. I am sure that the 2.3 rpm is a key component to all this, but as is the entire setup. This really confirms what i've been wondering about how this engine performs. Buschur really was after such a graph and has delivered. Nice
The BR RPM motor is awesome. Davids setup is spot on... it explains why I keep using his stuff. I can post another turbo on this 2.3...it won't do much as its no apples to Apple comparison . I wanted an awesome setup...this why I went this route.
I'd love to take it to every dyno and try every setup.... its not going to happen. It doesn't matter to me much anyway. I know what a good setup this is. Can I make more power...yep. do I want to or even plan on running it's at 30psi...doubtful. nobody is playing Dyno games...The setup is as I said sick.
Haha.... want to come see the car? I'll be at chuckawalla on the 18th.... ask nice and I might even take you on a ride.
I'd love to take it to every dyno and try every setup.... its not going to happen. It doesn't matter to me much anyway. I know what a good setup this is. Can I make more power...yep. do I want to or even plan on running it's at 30psi...doubtful. nobody is playing Dyno games...The setup is as I said sick.
Haha.... want to come see the car? I'll be at chuckawalla on the 18th.... ask nice and I might even take you on a ride.
With that amount of load time it would be in between a 4th and 5th gear pull which appears very misleading on the spoolup.
Im sure this setup is still miles ahead of the other offerings , but using a load time like that for a final number is a bit missleading , on the street in 3rd gear I bet it will not come close to those numbers in the low RPMs . Prove me wrong i hope!
03whitegsr, thanks for your technical correction. although I have no idea what you actually corrected. you are wonderful with theories. I will stick to my practical application. Everything I said is 100% true. stainless manifolds expel more heat into the engine compartment than factory cast manifolds. period. that heat heats up everything IN the engine compartment reducing the ability of engine to make power. I run cold air intakes on all my setups so that is not the solution to adding heat to everything metal in the compartment. If your theories say that it shouldnt happen then its your job to figure out why. I could really care less.
Re-read what he wrote. It makes perfect sense and is NOT a theory, but scientific measured fact. What you said about stainless as a material was not true. The end result (higher engine bay temps is still correct) because of the increase of surface area that the tubular manifolds have... as 03white stated. He's not attacking you, he's just explaining what you've experienced. Same team right?
And you're supposed to say "I couldn't care less less."
I understood. But the manifold I tried did not have significantly more surface area. It was short runner tubular. It was amazing how hot the engine compartment got. valve cover, IC pipes, intake manifold all get so hot they burn you when touched. While I didnt measure the 175-325 numbers I believe them to be spot on from what I have seen. In addition its next to impossible to have cold a/c here which I have seen on the one full race mani build I did here on evo 8. Even with oversize radiator the a/c barely kept car cool during hot summer traffic. these issues are simply not issues with factory cast manifolds with heat shields in place.
while I dont want to argue theories I am not even sure he, or you are applying it correctly. poor thermal conductance would mean less heat will go into stainless. But we arent referring to heat going in. Its the heat that goes off. Is that even thermal conductance? You weld. are you saying you have never noticed how fast stainless cools? or even manifolds themselves in the engine compartment? full race manifold can be touched after just 15 minutes cool down. cast manifolds need 45 minutes to cool before touching. Even in your kitchen the same applies. cast iron pans vs. stainless.
while I dont want to argue theories I am not even sure he, or you are applying it correctly. poor thermal conductance would mean less heat will go into stainless. But we arent referring to heat going in. Its the heat that goes off. Is that even thermal conductance? You weld. are you saying you have never noticed how fast stainless cools? or even manifolds themselves in the engine compartment? full race manifold can be touched after just 15 minutes cool down. cast manifolds need 45 minutes to cool before touching. Even in your kitchen the same applies. cast iron pans vs. stainless.
EvoM Guru
iTrader: (50)
Joined: Mar 2006
Posts: 9,675
Likes: 132
From: Tri-Cities, WA // Portland, OR