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Discussion Starter #1 (Edited)
Should I buy a stage 2 or stage 3 head ?
Mine will be a weekend driver ... with 3 to 4 trackdays per year.

VAC - BMW S38 Stage 2 Performance Cylinder Head

VAC - BMW S38 Stage 3 Performance Cylinder Head
Taffy's going to buy a VAC head for his M5 , should he go for stage 2 or stage 3 for a weekend driver and track day car ?

Has anyone actually used one ?

http://store.vacmotorsports.com/vac---s38-stage-2-performance-cylinder-head-p1293.aspx

http://store.vacmotorsports.com/vac---s38-stage-3-performance-cylinder-head-p1294.aspx
 

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My first Q,, is why ??

i am positive that there is a gain,, measured at least !!

but is it worth it,, i mean if you strip down the car and are in a search for the last available ponies ,,and best power to weight ratio i would do it,, but oem S38 head is flowing well,, and i am sure it is enough for what the engine is made for :santasmile2:
 

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Discussion Starter #4
Taffy's thinking is better to get a good straight head from a reputable source than buying a used one off eBay.

With the costs of getting something freighted here and past customs we can't afford to buy something that's not perfect.

The main reason is a good head , Taffy has decided to go Stage 2
 

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OK, I can see that. Cost certainly has to factor in.

What was the supposed benefit of the Stage 3 over the Stage 2? What about drawbacks? Is the Stage 3 less drivable on the street? Just trying to understand better.

Thanks again,

Eric
 

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Discussion Starter #8 (Edited)
Personally I think the standard set up of the S38B36 is enough for daily driving.

Modifications seem to greatly effect bottom end torque, have a look at the E34 M5 IMSA on YouTube, it can hardly get rolling from a standing start.


You can't seem to modify the S38 (other than a chip and exhaust) without effecting drivability or reliability in disproportionate amounts in comparison to the performance gain, it's already a near perfect balance of performance, drivability, reliability and economy in stock form. I call it the '///M-velope' .

Taffy always wants more power for early morning tollway blasts and track days , he doesn't drive his M5 as regularly as I do (did) and I think the Stage 2 is a good compromise for what he wants.

I think the Stage 3 would make the M5 a bit of a pig in traffic due to the effect on bottom end torque. Bigger ports drop air flow speeds and decrease mixing at part throttle low rpm operation.


,
 

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I have an Alpha N conversion (airflow meter delete to provide more air to the engine) on an E30 M3 and it worked well. Obviously I don't know about longevity yet........

My sense is that an Alpha N and Unichip solution could give the E34 m5 broadly as much of a boost as a new head. But it all depends on finding a reputable tuner that knows the cars.....otherwise your engine could have a very short life indeed.
 

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I have an Alpha N conversion (airflow meter delete to provide more air to the engine) on an E30 M3 and it worked well. Obviously I don't know about longevity yet........

My sense is that an Alpha N and Unichip solution could give the E34 m5 broadly as much of a boost as a new head. But it all depends on finding a reputable tuner that knows the cars.....otherwise your engine could have a very short life indeed.

I agree with MattH,,,,,,,,in every word

in my case B38 ... so much more low grunt oem RPM revlimit,, but resonatorflap delete,, and it was an awsome feeling
when the ponies came in through the port...

i did some experiment with airflow,, to much,,in the end

gorgeous induction sound,,,,,,, but,,,,, went to lean and destroyed the engine

and as Matt is mentioning let some PROPER guy who knows these engines ..recalibrate ... and use WIDEBAND controller if possible
 

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But,,, have you guys considered buying a B38 engine... complete

from EU ??
How much ?

My engine is 48,000 miles which is pretty low. I don't think there is a low mileage engine for sale in EU
 
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