twinscrew set-ups/kits

[Jon@Bimmersport]

check this out guys
http://maxbimmer.com/forums/showthre...77#post1383477

[black bnr32]

Originally Posted by Jon@Bimmersport

The most impressive is the NEW HKS based S/C kit from AA...we just finished a Level 2 on an MZ3 and it is the best of both worlds (power of a turbo, drivability of an S/C setup)

Sorry Jon, I have to correct you. The new HKS set up is not an improvement in the illusive "best of both worlds" search. It is very, very similar to the outgoing Rotrex set up and should be known to put out very, very similar performance. I mean, you've installed both so I'm kind of confused on why you think this, no offense!

That said, the kit seems to be top notch!

OP: An aftercooled centrifugal supercharger set up will be just as complex as a turbo set up. A twin screw set up *should* be simpler (I haven't owned one).

[sthomas]

Originally Posted by Steve30

If tracking the car is your biggest concern then I would say go with the twin screw because its strong point is low to mid range torque.

Tracked cars do not need 'low to mid range torque'. Quite the opposite.

Originally Posted by Jon@Bimmersport

If your dedicated track, NA only...if occasional..then anyway you go, better water cooling and OIL cooling is an absolute necessity especially for turbo (considering the S/C uses an independent oil system with cooler). Theres a lot of things to going FI people dont get, it doesnt stop at the S/C kit. Oil coolers, better higher flow/capacity cooling systems, clutches etc are all needed when stuffing double the power your engine was designed to make (or in other words - double stress, and more heat).

It really depends on what you end up doing, and what you want out of it. I've been tracking my e36 (3.2L OBD1 conversion with RMS Stage 1 kit) for a few years now and it runs fine. Certainly the power drops off as the heat sets in on the track - since Stage 1 does not have an intercooler or injection. I don't run an oil cooler (the Vortec S/C uses the engine oil) - but I do use good oil and change it often. I ran the original rad until quite recently (a bent fan-blade took it out last Sept and Mosport). I also installed the e34 M5 clutch with a light-weight flywheel from UUC.

MarkD tuned the motor, so I am already running rich enough to avoid detonating the motor at the track. However, I am toying with the idea of alcohol injection to help with the heat-soak (which is only apparent on the track).

[Jon@Bimmersport]

Originally Posted by black bnr32

Sorry Jon, I have to correct you. The new HKS set up is not an improvement in the illusive "best of both worlds" search. It is very, very similar to the outgoing Rotrex set up and should be known to put out very, very similar performance. I mean, you've installed both so I'm kind of confused on why you think this, no offense!

That said, the kit seems to be top notch!

OP: An aftercooled centrifugal supercharger set up will be just as complex as a turbo set up. A twin screw set up *should* be simpler (I haven't owned one).

No offense taken,

Your conclusion is based off of what information I have to ask...? They are known to put out similar peak #'s in kit form, driving wise the HKS is known for more low-midrange power which will carry up top. That is how I got to my answer, although the flow charts seem the same...when going to a stage 2 unit the HKS based car will outperform the rotrex. I havent tested back to back on the track (or driven any on the track for that matter), but this is comming from the engineer at Active. For a street car, the HKS will be a much better choice. Remember, 90% of the people buying these products daily drive their car...given my statement, what would you choose? Either choice does not make one or the other right or wrong as this whole FI world comes down to personal preference. One thing you are forgetting is beyond what is offered now as a kit and can be attained in the future. I am on the fence about throwing away my vortech based kits I have...as I can spin the HKS double the speed of the vortech I use.

Sthomas,

I never questioned the possibility of running without said items but why? The only other one I know running a heavier setup than yourself would be Tommy, and was running a non vanos setup (then again the rods are huge compared to M3 and can handle more stress over a longer time). I would run the oil cooler on any FI setup, for the same reasons BMW incorporated it into any factory NA car made for performance driving - not for liability, but for long term durability. Again, there is no argument as to what should be done. Then again, with your engine setup you are increasing your engine output by ~50%...opposed to my statement based on almost 100% increase in power.

[e30_kid89]

One thing in regards to oil cooling which does a lot more harm than good I notice on street-driven S/C e36s is nobody uses an oil cooler thermostat which is vital since the oil will take a really long time to warm up to properly lubricate and may cool down too much while doing highway driving again making the oil loose its ability to properly lubricate. The S54 oil filter housing has a built-in one for a reason.

Without the thermostat most guys with primarily street-driven cars are better off without the cooler.

[black bnr32]

Originally Posted by Jon@Bimmersport

No offense taken,

Your conclusion is based off of what information I have to ask...?

Just Mad dog 20/20's thread on bimmerforums.

[black bnr32]

Originally Posted by Jon@Bimmersport

I am on the fence about throwing away my vortech based kits I have...as I can spin the HKS double the speed of the vortech I use.

Looks like the HKS is limited to ~ 15psi IIRC.

Edit: not totally apples to apples given the mods, but here's Mad dog's HKS vs the AA Rotrex dyno graphs. The lower half of the dynos are really similar, no?
http://forums.bimmerforums.com/forum...305271&page=13

also,
C38-81:
90k rpm max impeller speed
952.5 CFM max flow
1:7.5 drive unit ratio

HKS GTS8550:
100k rpm max impeller speed
918 CFM max flow
1:9.4 drive unit ratio

[Jon@Bimmersport]

If you are refering to page 13, the dyno graph is of v1 tune and v2 for his HKS kit. Mad dog didnt install both kits for a back to back comparison. One of the reasons for his top end hiccup was his plugs.



Also if you read the thread, many people agree to the conclusion that the HKS does produce more midrange...including the OP your qouting. Which is why AA chose this kit, to give an option to those who do want more low/midrange power compared to traditional centri based kits.

The C38 you listed is for E46 M3 FYI..E36 kits use C3871, now the only one using C38-81 is the 330 based kits.

[Jon@Bimmersport]

Just to add:

C38-71 flows 900cfm @15degrees C @ MAX impeller speed

(CFM calculation is Kg/s X 1731.8)

Anyways, what you want to compare is a flow chart...not CFM at max impeller speed as the blowers usually arent spun at max impellar speed on an off the shelf kit.

[Daxxas]

Good rule to follow, Take the number you think it's going to cost you to build and tripple it. By the time you add up all the hardware, tuning, and jewelry for the wife. If you think it'll cost 5k, it'll probably be 10-15k by the time your hair stops falling out. That being said, i'm quite happy with the power my s50 with the vortech s/c.

[iverson03tj]

Originally Posted by e30_kid89

One thing in regards to oil cooling which does a lot more harm than good I notice on street-driven S/C e36s is nobody uses an oil cooler thermostat which is vital since the oil will take a really long time to warm up to properly lubricate and may cool down too much while doing highway driving again making the oil loose its ability to properly lubricate. The S54 oil filter housing has a built-in one for a reason.

Without the thermostat most guys with primarily street-driven cars are better off without the cooler.

Where can i get a oil cooler thermostat and is it hard to install?