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Discussion Starter #1
Any idea what is the boost limit that stock Exige S240 supercharger can take? Take into consideration of long lasting and continuous lapping in track.

I've already upgraded to 3.0" pulley which should be around 9.5psi boost. And thinking of going 2.8" pulley. But worry that the supercharger can't last.

Thanks for your input.
 

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I've only seen 2.4" pulley which produced about 15 psi (post heat exchanger).

The supercharger will last, the motor and transmission will not (for "continuous lapping") -- but also depends on how hard you drive on the track.

I ran a 2.5" pully for a long long time and the M62 SC never had a problem (my motors/trans did have problems).

Here is a pretty neat video of a V8 motor built specifically for forced induction application (take note of the o-ring groves in block):


Rob
 

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14000 rpm is the max suggested shaft speed...
 

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Stock pulley size running at 10000rpm right?

14000rpm equivalent to what pulley size?
You'd have to measure your crank pulley and figure out your ratio, I don't have one to measure at the moment.
 

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Stock pulley size running at 10000rpm right?

14000rpm equivalent to what pulley size?
I did the calcs some time ago, as I recall it was around 14000 rpm @ 8500rpm with 3.0 pulley.

Pulley Calculator

Power Driver Pulley Diameter (Crank Pulley): 5.25
Driven Object Pulley Diameter (SC): 3.0
Belt Length (Exige S): 76.4
Input (Driver) RPM (Engine RPM): 8500

Answer: 14875 SC shaft rpm

But like I said, I ran 2.5" pulley for a long time (shaft 17850) without the M62 having any issues (on track).

... but like I said, the M62 should be low on your worry list.

PSE do rebuilds for the M62.

Rob
 

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After having a MP62 fail within a few months of install, with the standard sized pulley, forgive me, but I don't trust them to be over-spun.
 

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Sorry to hear that, mind if I ask what failed in it?
 

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Bearings furthest from the nose failed, causing the impellers to make contact with each other and the case.
 

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I have always accepted that the maximum design speed for an M62 was 16k. I did this research a number of years ago so maybe my memory is getting old and crusty but it would make sense that the OEM isn't pushing it past max.

-Michael
 

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You can make nearly 300whp with 3" pulley with the M62, stock compression, a little head porting, headers, decat, decent intercooling, cams, and a decent tune. Drop 10-15wheel off that without the cams...

We've been down this path from so many angles in the past. There's really no need to reinvent.

The 2.5" pulley thing isn't the way to go about it with a M62. Forget about pulley speed, just look at the compressor map. You end up spending more energy generating heat than you do moving air (that's hyperbole, but you get the idea). I pulled a compressor chart that I marked up from the "archives" of posts about this stuff.

Also adding a chart of the TVS so that you can see how the chart should look for running more boost (which is what you're trying to do by running a smaller pulley obviously)...

The green dotted lines are blower RPM. Stock crank is about 5.3". Stock Exige pulley is 3.2" or so...

The numbers scattered about the chart "island rings" are efficiency indicators.

You can figure boost from pressure ratio by simply by (PR-1)x14.7=Boost at sea level (assuming zero vacuum in front of the rotors, but go ahead and assume that for now;)).

You can't even map a stock pulley fully, let alone a 2.5" pulley... The blower efficiency would be less than 50% at that point anyway, so not a lot point in doing so anyway when there are far better blowers for the job...


-PV
 

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The M62 is generally very robust and can be pushed far past the end of the compressor map and even the spec limit.

The down side as phil pointed out is that you quickly get to the point where the gains in air you are moving is negated by the much hotter intake charge (as well as parasitic loss used to turn the blower that quickly)... and it is simply not worth it. A larger more technologically advanced blower like the TVS 1320 is a BIG step up once you are trying to get past the say 300hp range on a 2zz.
 

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Discussion Starter #14
But to get pass 300hp we need too much of supporting mods like engine internals and also the fragile gearset.
 

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The gears are weak at any power level and MANY people have been able to get a LOT of miles and track times from the stock tranny. Much of the stock tranny failures are due to driver not power.

300bhp, is a cake on this motor without reliability issues... Even 300whp hasn't been an issue... Much over that and yes, you're pushing things, but still plenty of examples doing it.
 

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For me the limit was about 250whp with 2.8" pulley and 8.8 pistons. Probably add 25hp with stock compression. A mouse nest in my intake locked mine up but it was an easy fix. Hoping a TVS will add at least 50hp.
 

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We made 299 Whp (DJ #s) with 10 psi and built engine we homologated for WC back in 2010 that was limited by the rules at that time and required to run on spec fuel (Sunoco 98 unleaded).

Then after SCCA detuned the spec we had to run the stock pulley and made 260 Whp.

We've also made near 300 Whp with M62 non-intercooled and using E85 pre-injected on 100% bone stock engines with only 8.5 psi. This lowers the air temp better than any air-to-air intercooler and the fuel just works incredibly well.

We've since improved race petrol fuel tuning to over 315 Whp with M62 with engine tuning and 11 psi, but takes a lot of work. The main issue is controlling the temp.

The TVS blowers are more efficient and therefore less heat output.

Improve the engine and you need less boost to make same or better power. Not to mention improved reliability, less heat, and less stress on the engine.
 

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Discussion Starter #18
good news Kris :)

seems like the engine really need to be rebuilt. All this while I was looking for easy power gain from the MP62 pulleys :p



We made 299 Whp (DJ #s) with 10 psi and built engine we homologated for WC back in 2010 that was limited by the rules at that time and required to run on spec fuel (Sunoco 98 unleaded).

Then after SCCA detuned the spec we had to run the stock pulley and made 260 Whp.

We've also made near 300 Whp with M62 non-intercooled and using E85 pre-injected on 100% bone stock engines with only 8.5 psi. This lowers the air temp better than any air-to-air intercooler and the fuel just works incredibly well.

We've since improved race petrol fuel tuning to over 315 Whp with M62 with engine tuning and 11 psi, but takes a lot of work. The main issue is controlling the temp.

The TVS blowers are more efficient and therefore less heat output.

Improve the engine and you need less boost to make same or better power. Not to mention improved reliability, less heat, and less stress on the engine.
 

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I know its tempting to slap a pulley on there...but the truth is all you'll get is a "glory run"..aka "one hit wonder"...aka "grenade"...etc

ask to see dyno runs of cars that do 4-5 pulls consecutively and you'll see what I mean. We've seen as much as 23 Hp loss with heat soak on cars running only 10 psi. Not to get off topic, but that's why we suggest considering our NA engines when looking for ~ 250 Hp without any of that drama and you save weight in the process.
 

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great info guys. I recently purchased a katana2 kit and yes its a big improvement but as we all know. WE need MORE. So I too was thinking of slapping a 3" on it. My question to you was the cooling. As i am not intercooled i was thinging of doing it with a water meth injection pre injected into the throttlebottle. Any suggestions on this. Im running a stock engine with upgraded clutch.
Any info or suggestions would be much appreciated. Im very new to this but im not afraid to try.
 
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