best turbo for street/mostly track 930?
#1
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best turbo for street/mostly track 930?
I have a fairly modified 930 that makes around 405hp-460ft/lbs at .9 bar +/-. The mods are limited to bolt ons, stock displacement, C/R. What I am finding is that the maximum boost begins to fall off as the revs climb above 4500, it seems like the turbo just can't make enough volume. It's a K2700, although I can't say what model as I purchased the car used. I have virtually no lag, since I have B & B headers, and run a 3 inch straight pipe, a'la 935's, for a "muffler". Anyone have any subjective experience with Kokeln, Turbonetics, Huntley etc.. or other aftermarket hybrids, or just K29's?
#2
I'm certainly no expert in this area but the Porsche 911 Performance Handbook talks about the limitations of the CIS (if thats what you have). Basically it says that a US CIS has a practical limit of 400hp and a euro CIS has a practical limit of 450hp... You can check out the electromotive TEC-II,haltech or motronic systems for aftermarket... There are also a fuel enrichment devices that work in conjunction with your CIS, I don't know what the practical limits of these are. You could use a fuel enrichment device with a twin-plug setup, this should give you enough protection to run a higher boost 1.0-1.2 (this is what I'm going to be doing) with an HKS boost controller.
That's about the extent of my knowledge on this subject.
-LeoD
That's about the extent of my knowledge on this subject.
-LeoD
#3
RL Technical Advisor
Hey Randy:
Its just my opinion, but I think you are looking in the wrong direction. That K27-200 turbo works very well up to 450-475 HP and I do not think this the problem.
The K-29 is an old design that has many lag problems. We no longer use them.
You did not say what cams you have or whether your intake system has been modified. Please remember that any engine is simply an airpump and unless you the necessary changes to allow air to move THROUGH the engine, everything else is moot.
We do lots of Turbo's here in the 3.4 to 3.5 litre range that make 450-460 HP at 1 bar, max. All have SC or 964 cams, modified, flowed and equalized intake manifolds with larger diameter alloy injector blocks, and heavily opened and flowed heads. We use the C2 intercooler to maintain low charge-air temperatures and all have twin-ignition. Airflow meters are modified for more air and fuel delivery and will work very well up to this power level. Fuel distributors are also modified and then setup on the dyno when the engine is broken in to ensure that there are no lean spots in the fuel curve........
Lastly, we do not use Electromotive ignitions in Turbo applications due to the lack of boost retard. The OEM distributor is converted to twin-plug operation and an additional CD box and coil is added.
Look beyond what you currently have and plan the requisite internal mods to utilize what you have more efficiently.
--
Steve Weiner
Rennsport Systems
Its just my opinion, but I think you are looking in the wrong direction. That K27-200 turbo works very well up to 450-475 HP and I do not think this the problem.
The K-29 is an old design that has many lag problems. We no longer use them.
You did not say what cams you have or whether your intake system has been modified. Please remember that any engine is simply an airpump and unless you the necessary changes to allow air to move THROUGH the engine, everything else is moot.
We do lots of Turbo's here in the 3.4 to 3.5 litre range that make 450-460 HP at 1 bar, max. All have SC or 964 cams, modified, flowed and equalized intake manifolds with larger diameter alloy injector blocks, and heavily opened and flowed heads. We use the C2 intercooler to maintain low charge-air temperatures and all have twin-ignition. Airflow meters are modified for more air and fuel delivery and will work very well up to this power level. Fuel distributors are also modified and then setup on the dyno when the engine is broken in to ensure that there are no lean spots in the fuel curve........
Lastly, we do not use Electromotive ignitions in Turbo applications due to the lack of boost retard. The OEM distributor is converted to twin-plug operation and an additional CD box and coil is added.
Look beyond what you currently have and plan the requisite internal mods to utilize what you have more efficiently.
--
Steve Weiner
Rennsport Systems