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Discussion Starter · #1 ·
Contemplating my next project...

Thinking of a sand rail for street use...

Either a Mazda rotary (which I know nothing about) or a 2.0ish liter VW air cooled.

Want something I can play with on the street with 93 octane pump gas.

Would like to make about 300-350 HP with either, which I don't think will be an issue.

Blow through with intercooler?
Draw through without?
Turbo size?
Carb size (500 cfm holley?)

Could use some advice here.
 

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Kelly's Nightmare
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rotary + turbo= Primed Grenade

If you choose to go with a Rotary you can use a much larger turbo due to it's increased efficiency and rpm. Not uncommon for a 1.3L rotary to be sporting a 74/76mm turbo or even a 88mm depeding on the application.

Cant help with the VW stuff though
 

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الكتاب ا
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For the 2.0 to 2.3L range, I recommend a T3/T4 turbo. Use a 50-trim T4 compressor wheel and a stage 2 T3 turbine wheel. There are a number of different housings you can put these in for fitment.

I'd go just a hair bigger for the rotary's turbo.
 

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Like 850sportman said, The rotary will need a MUCH larger turbo then the VW motor would.

I, personally, would do a honda motor if you could...they are very easy to work on and don't explode every 15 seconds. We do alot of work with rotary powered cars, but what a pain in the ass they are!

It's insane.


Sounds like a pimp project tho, good luck either way.
 

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Discussion Starter · #5 ·
Yeah, I had a buddy suggest the rotary. I had the same impression, they were just a grenade waiting to have the pin pulled.

Seems like every boosted rotary I've ever seen either cleans the apex seals off, or melts the enter center assembly.

I guess on the plus side, they're cheap. But, I really don't want something I have to wrench on constantly... I've got that now, and that's what I want to get away from.

I really am attracted to the air cooled motors for the simple fact of all you have is oil... Gear lube in the transmission, and nothing more. Just pure simplicity... What's even neater is the fact that cams and such seem to cross over very well to what I know about V8s.

Can I get away with a non-intercooled application? Something like 8:1 compression (or lower) and push about 10-15 PSI through it? I had a 9.5:1 BBC with a small blower years ago and ran 7 PSI through it.

Would seem that with the increased efficiency of a turbo (to my limited knowledge about them) that what I'm after isn't impossible or impractical.

What am I looking at for cost on said turbo?
 

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Discussion Starter · #7 ·
Air cooled + non intercooled turbo + vw + 15psi + carb

Thats too much scary for my tastes...
What do you mean?

A 8:1 motor with 15 PSI is going to have a final mechanical (not dynamic) compression of 16.15:1.

The same motor with 7:1 will be 14.15:1.

I've ran BBC's with 9.5:1 and 7PSI, which equates to 14.05:1.

I'd think that if the motor had adequate cooling, 15 PSI would be doable... I thought turbos created less intake temperature than roots blowers? Am I wrong?
 

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You might want to look into a 4G63 out of a first gen dsm since they come factory turbo'd. Stock they run fairly well but with some upgrades they can hold their own.

Jared
 

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i got a 2jz engine if ur interested comes stock with forged internals
 

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Contemplating my next project...

Thinking of a sand rail for street use...

Either a Mazda rotary (which I know nothing about) or a 2.0ish liter VW air cooled.

Want something I can play with on the street with 93 octane pump gas.

Would like to make about 300-350 HP with either, which I don't think will be an issue.

Blow through with intercooler?
Draw through without?
Turbo size?
Carb size (500 cfm holley?)

Could use some advice here.
Go with a BorgWarner AirWerks turbo. The pump gas hp figures are just a estimate. To know for sure you would have to do a match and see where it falls on the map assuming you can run about 15 psi of intercooled boost.

Part No. Model Inducer (mm) Hp level
177257 S200 50.7238 (upto 480 hp (race gas)~ 250-300 pump gas)

177268 S200 55.8038 (upto 600 hp (race gas)~ 350-420 pump gas)
 

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Go with a BorgWarner AirWerks turbo. The pump gas hp figures are just a estimate. To know for sure you would have to do a match and see where it falls on the map assuming you can run about 15 psi of intercooled boost.

Part No. Model Inducer (mm) Hp level
177257 S200 50.7238 (upto 480 hp (race gas)~ 250-300 pump gas)

177268 S200 55.8038 (upto 600 hp (race gas)~ 350-420 pump gas)

For the price of those units a standard T3/T4 GT would be a better suited unit and much more flexible on A/R's, trims and avialable comp covers.
 

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Discussion Starter · #18 ·
Are you looking for a RWD application? What transmission would you like to use?

Justin
Yes, looking at something like this: http://www.thesamba.com/vw/classifieds/detail.php?id=643376

In fact, that's pretty much what I'd build, but with carbs instead of the injection. Throw some street tires up front and a 315 drag radial out back and have some fun...

This is extremely cool too, but the compression is too high for turbo/street use. http://www.thesamba.com/vw/classifieds/detail.php?id=436181

If I were to buy a frame, it'd either be this one from "The Buggy Shop":


Or this one from Prowler Chassis, called the Hi-Jumper Sprite IV:



I like the mid engine design better, as it will help keep wheelies under control when it's in boost.
 

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Throw a stock 4g63 in it and with a small turbo on it(16g, 20g, 50trim). Grab the motor, harness, and ECU from a junk yard and slap it in. A stock engine will make that power all day long and will be super cheap to do.
 
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