High Compression Turbo'd Motors....
10-06-2003, 01:21 AM
#1
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Join Date: Oct 2001
Location: Peoria, AZ
Posts: 10,906
Anyone here using so called high compression rotors in boosted application? Complimented by a very cool intake charge, a so called high static compression of only a minor increase( 9.0:1 vs 9.7:1) should have no more dentonation than a motor with lower static compression rotors, right? I don't care about anyone input that does not have personaly experience, there is so much bullshit on this topic from people who jump on bandwagons, so please if you don't have experience, keep your assumptions to yourself 
10-06-2003, 02:28 AM
#2
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Join Date: Oct 2003
Posts: 177
I do I do!
Using S4 N/A rotors here, and before anyone says not to listen to me because my motor is now dead, the reason THAT happend was that my wastegate line fell off and boost went to 18psi, up from 7 (my fault).
It didn't even dotonate to the best of my knowledge, i certainly didnt hear any thats for sure. All my apex seals are still there, it seems it has killed a side seal.
I'll never build/buy a motor with low comp rotors, I think having low comp rotors is just a band aid solution to poor tuning/setup.
The response is great, the turbo spools up much earlier aswell. I have a front mount IC on my car aswell and a cold air fed filter, so air temps are always relativly low.
So there ya have it. I personally am a big fan of high compression motors in general, both in N/A and turbo applications.
Using S4 N/A rotors here, and before anyone says not to listen to me because my motor is now dead, the reason THAT happend was that my wastegate line fell off and boost went to 18psi, up from 7
It didn't even dotonate to the best of my knowledge, i certainly didnt hear any thats for sure. All my apex seals are still there, it seems it has killed a side seal.
I'll never build/buy a motor with low comp rotors, I think having low comp rotors is just a band aid solution to poor tuning/setup.
The response is great, the turbo spools up much earlier aswell. I have a front mount IC on my car aswell and a cold air fed filter, so air temps are always relativly low.
So there ya have it. I personally am a big fan of high compression motors in general, both in N/A and turbo applications.
10-06-2003, 10:52 AM
#3
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Join Date: Sep 2002
Location: Savannah, Ga
Posts: 2,763
Someone I know was running 9.7 rotors in a S5 TII with a stage 4 hybrid turbo with a SP motor. Full boost by 1800 rpm in 5th gear. He was still running the stock TMIC, and 91 octane, and nver had any detonation problems at 10 PSI. HKS FCON, and I think he had larger injectors in th esecondaries. The engine builder screwed up, and the compression never went past 90K, then it blew an oil control at 4K miles. All of the apex and side seals were perfectly fine, just a bad oil control ring. He never dynoed ot track tested it, but he was walking good on mid to low 13 sec cars.
Youll have to wait a few months if you want to hear how mine turns out. Im going to be running twin T3's on my freshly rebuilt S5 n/a motor.
Youll have to wait a few months if you want to hear how mine turns out. Im going to be running twin T3's on my freshly rebuilt S5 n/a motor.
10-06-2003, 11:41 AM
#4
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Join Date: May 2002
Location: California
Posts: 22,465
id use the s4 rotors, its not hard to get into detonation, we had the 20b pinging at 7 psi on 91 octane, this weekend.
my opinion is that unless you're right on with your tuning you're gonna be pulling the engine apart again
mike
my opinion is that unless you're right on with your tuning you're gonna be pulling the engine apart again
mike
10-06-2003, 09:46 PM
#7
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Location: Bay Area, CA
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Originally Posted by vosko' date='Oct 6 2003, 05:59 PM
when i build another engine will be with high compression n/a rotors!
10-06-2003, 09:50 PM
#8
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Join Date: Jul 2001
Location: NJ
Posts: 17,839
Originally Posted by 13BAce' date='Oct 6 2003, 10:46 PM
I've been thinking of throwing a 60-1 onto the NA motor. I could always port match a TII upper intake manifold to the NA lower.
10-06-2003, 09:57 PM
#10
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Join Date: Oct 2001
Location: Peoria, AZ
Posts: 10,906
Originally Posted by j9fd3s' date='Oct 6 2003, 11:41 AM
id use the s4 rotors, its not hard to get into detonation, we had the 20b pinging at 7 psi on 91 octane, this weekend.
my opinion is that unless you're right on with your tuning you're gonna be pulling the engine apart again
mike
my opinion is that unless you're right on with your tuning you're gonna be pulling the engine apart again
mike