Forget SuperChargers - Lets Talk Twin Turbos
01-28-2003, 01:14 AM
#76
Rennlist Member
Twin turbo 928 is a good idea and there is no reason why a nice 500 rwhp tt version would not be doable with all the reliability of a 944 turbo, and better than supercharging, less trans smashing torque at low rpms!
My version would have supported over 1000 hp at the crank and the goal was to break the sledgehammer record, however, my intrests right now are in normal aspiration engines in the 700-800 crank hp range.
I believe that NA airflow into an engine, and how it is combusted is what performance and efficiency is all about....and then you just add pressure!
When it is time to make a withdrawal from my account in my "boost bank", it will be a damn big one!
Pistons are no longer available, just the turbos.....
Good luck,
Marc
DEVEK
My version would have supported over 1000 hp at the crank and the goal was to break the sledgehammer record, however, my intrests right now are in normal aspiration engines in the 700-800 crank hp range.
I believe that NA airflow into an engine, and how it is combusted is what performance and efficiency is all about....and then you just add pressure!
When it is time to make a withdrawal from my account in my "boost bank", it will be a damn big one!
Pistons are no longer available, just the turbos.....
Good luck,
Marc
DEVEK
01-28-2003, 01:11 PM
#77
Three Wheelin'
Join Date: Nov 2001
Location: Northern Kentucky
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Marc,
You need to build a 928 TT monster! 6+ liters of displacement with about 1 atmosphere of manifold pressure, then add the Motec and stand alone ignition system. It would not be that difficult, just a bit costly. The Motec alone is over $4,500...then you spend a month getting a correct program. I considered it on mine, but that is a huge percentage of the value of my car. I needed a more cost effective option.
I am in the process of getting a compressor map for my RHB6 from IHI. Luckily, they are willing to send this information to me, some places won't. It just depends on how you ask and who you ask... From there, I can look and see if I am still in the good efficient range of the compressor. Gut feel tells me that compressor should be ripe up to 10 or 12 psig above atmosphere. The RHB 6 series is supposed to support up to 300 HP.
My goal is about 52 in Hg, or around 11 psig at the manifold.
My other mod will be to install an electronic wastegate control to help avoid the initial cracking of the wastegate valves I get now at about 5 psig. This slows the boost climb from 5 psig on up. The electronic controller will eliminate this cracking, then pop the valve at the precise time....hopefully not too late. I have selected a Greddy Profec B because of its simplicity.
8.5:1 compression is perhaps a tad bit high for huge boost numbers, but I feel confident I'll be safe with 11 psig and 93 octane. Today, I can fill the tank with 87 octane, run 8.5 psig to the manifold and get no detonation whatsoever.
I'm covering every base before I do anything...Fuel, ignition, intercooler, compressor map, compression ratio....so an and so forth...
You need to build a 928 TT monster! 6+ liters of displacement with about 1 atmosphere of manifold pressure, then add the Motec and stand alone ignition system. It would not be that difficult, just a bit costly. The Motec alone is over $4,500...then you spend a month getting a correct program. I considered it on mine, but that is a huge percentage of the value of my car. I needed a more cost effective option.
I am in the process of getting a compressor map for my RHB6 from IHI. Luckily, they are willing to send this information to me, some places won't. It just depends on how you ask and who you ask... From there, I can look and see if I am still in the good efficient range of the compressor. Gut feel tells me that compressor should be ripe up to 10 or 12 psig above atmosphere. The RHB 6 series is supposed to support up to 300 HP.
My goal is about 52 in Hg, or around 11 psig at the manifold.
My other mod will be to install an electronic wastegate control to help avoid the initial cracking of the wastegate valves I get now at about 5 psig. This slows the boost climb from 5 psig on up. The electronic controller will eliminate this cracking, then pop the valve at the precise time....hopefully not too late. I have selected a Greddy Profec B because of its simplicity.
8.5:1 compression is perhaps a tad bit high for huge boost numbers, but I feel confident I'll be safe with 11 psig and 93 octane. Today, I can fill the tank with 87 octane, run 8.5 psig to the manifold and get no detonation whatsoever.
I'm covering every base before I do anything...Fuel, ignition, intercooler, compressor map, compression ratio....so an and so forth...
