Let's talk boosted M42's

[MF DOOM]

This is worth sharing.

http://www.m42club.com/forum/index.php?topic=14554.30

[wazzu70]

Not that it matters too much, but so do you get 30% worse mileage?

Yes.

[Vivek]

E85 has the benefit of allowing a more aggressive timing map due to the cooler temps and higher octane. I gained 30+ hp with my last track car on E85 vs 91 with extensive tuning (this wasn't on an m42)

The biggest issue with e85 is the need for much larger injectors. e85 requires roughly 30% more fuel than 91. You don't have to upgrade the entire fuel system as stated previously. The lines you currently have will do just fine. And in a turbo application a walbro 255 is already necessary and can still support e85. It's not much more expensive to go e85 over 91.

Not that it matters too much, but so do you get 30% worse mileage?

[MF DOOM]

My understanding is they have not built kits in what 6+ years?

Yes. Not sure how long ago but they no longer buid them.

maybe. placing a turbine in your exhaust path impacts the VE of the engine. that's about it.

ahh.. i knew the answer was going to make me feel stupid ha

[future rs]

E85 has the benefit of allowing a more aggressive timing map due to the cooler temps and higher octane. I gained 30+ hp with my last track car on E85 vs 91 with extensive tuning (this wasn't on an m42)

The biggest issue with e85 is the need for much larger injectors. e85 requires roughly 30% more fuel than 91. You don't have to upgrade the entire fuel system as stated previously. The lines you currently have will do just fine. And in a turbo application a walbro 255 is already necessary and can still support e85. It's not much more expensive to go e85 over 91.

[wazzu70]

maybe. placing a turbine in your exhaust path impacts the VE of the engine. that's about it.

This is it. The turbine uses exhaust gasses that would be created anyway, but the backpressure changes the VE of the engine.

[M-technik-3]

Why does no one DASC the m42?

My understanding is they have not built kits in what 6+ years?

[decay]

Or am I over thinking it?

maybe. placing a turbine in your exhaust path impacts the VE of the engine. that's about it.

[MF DOOM]

Are you guys referring to lag as power loss? What am I missing here? Turbo runs off exhaust. Making power from the engines waste sounds free to me. Or am I over thinking it?

[wazzu70]

A turbo still consumes power to make power. The turbos just are much more efficient than a belt driven supercharger.

[MF DOOM]

turbo robs power? wut..

[decay]

I'm no pro, but my personal opinion is that supercharging is much more limited than turbocharging, and it'll heat up the air with no intercooler to cool it down. It'll also rob a percent of your power, and I believe that this percentage increases with higher boost PSI's since you'll be putting a bigger pulley on for more boost. That and a DASC is hard as hell to find.

you can intercool a roots, it just works differently. jackson racing used to make setups like that for honda/miata.

turbos/supers both rob power, just in different ways. no free lunch, or we'd have a perpetual motion device.

[Vivek]

Why does no one DASC the m42?

I'm no pro, but my personal opinion is that supercharging is much more limited than turbocharging, and it'll heat up the air with no intercooler to cool it down. It'll also rob a percent of your power, and I believe that this percentage increases with higher boost PSI's since you'll be putting a bigger pulley on for more boost. That and a DASC is hard as hell to find.

[decay]

Why does no one DASC the m42?

everyone who isn't scared off by converting to serpentine for it just goes turbo instead.

if someone made a centrifugal for this engine, i'd be on it, but i can't use a roots.

[CrusherCurtis]

Why does no one DASC the m42?