So I picked up a 2.6" pulley that I've been staring at all Winter. I picked it up for a good deal from a member on here. But I'm on the fence if I should bolt it up or not. I currently have an OTTP stage 2 (2.8" pulley), Heat exchanger, Dual pass, Meth, OTTP long tube header and 2.5" catback. So I have all the supporting mods to run it I just don't know how reliable it is. The reason I'm on the fence is this car is my DD. I don't really feel like taking a big risk blowing it up. Even though I know theres always a risk modding cars. I am going to run a conservative tune. Not going to push my AFR to the edge. I know a few guys on here that will chime in with experience. But any good and bad points, fire away.

 

i have meth, dual pass heat exchanger. full exhaust..

I'm sure if you aren't always constantly punching it, it should be just fine, especially with meth

I wish i could find somewhere that will bolt up my 2.6. I can't get the damn stock one off.

 

be a man go 2.5 :P

jk free bump

if it was ME I wouldnt, I know I would hit pedal too much.

 

I knew you would be one to answer haha. I saw the 2.6" in your bet thread you got going. Bolt that thing up so I can win $5! Lol I honestly hardly rod on my car. I tend to save it for the track.

Haha I know it's hard to contain sometimes

 

Germans won't touch my car..
I found one place that will do it but they want 120 euro, which is like... 160 dollars.. to bolt it up

 

i'm just gonna' buy the puller myself..

 

Aw that sucks. It's not like it's a difficult job. But ya gotta pay to play

 

with meth, dual pass, and h/e you will be fine. just set your rev limiter to like 7000, because anything over the that kinda drops in power, I was running the 2.6 for 4 months as my DD with just a h/e and I haven't had 1 problem.

 

Holy heat soak haha. Power wise notice a big difference?

 

well I wasnt really heat soaking because it was a bit cooler out, but yes your low end power is awesome, I experimented with shifting at lower rpms like 7000 and it was indeed great. I actually put a 2.8 on and now when I'm at lower rpms at go wot it bores me :yawn: so I will do some cooling mods and put my 2.6 on soon. the 2.6 defiantly is amazing.

 

Im running a 2.6, ported head, ported sc and ported lower mani oh and water/meth. Only cooling mods besides water/meth is my 4gal flow thru tank. Its great for a d/d for me. My iats never get higher then 125* on a 2.6 after many back to back pulls.

 

now which port job you think created the most cooling effect? the lower IM? or is it the combination of it all?

 

you seem like you have the head on your shoulders/ and mods on the car to be wise in putting it in. i say go for it.

 

What do you need a pulley for? Run it right on the hub!

Steven Fit's MP90 testing got me thinking about what it would take to produce the same amount of CFM from the M62 compared to a 3" pulley on the MP90. It turns out that pulley size is a 2.4". Meaning, per engine revolution, a M62 with a 2.4" pulley would put out as much CFM as a MP90 with a 3".

Steve's MP90 was a Gen III design compared to the M62's Gen V design. So the M62 is much more efficient.

With a 3" pulley on a MP90 the blower will hit is Maximum efficiency by 6500rpms. That is why Steven never pushed it further.

With a 2.4" pulley on a M62 the blower will hit is Maximum efficiency by 6000rpms. I believe that running the M62 to 6500 would produce better results then Steve's MP90 to 6500rpms.

309/278


From 0 to 6000rpms both blowers are going to be putting out the same amount of CFM. But the M62 is going to be much more efficient. The parasitic engine loss and charged air temps will be lower. After 6000 rpms the MP90 is still within its efficient while the M62 starts to drop out of it. BUT just out of its efficiency range, the M62 is still more efficient then the MP90 in its efficiency range!

Obviously it is not smart to push any blower too far out of its efficiency range. I would not push a 2.4" pulley past 6500 just like I will not push the 2.6" pulley on my car past 7,000. I made 303/273 on my 2.6".

I guess my point is that if you have the proper cooling mods and a good tune, you can run a 2.6" without a problem.

 

Just the man I love to chime in. Thanks for the info. God I wish you lived closer or I would be giving you some porting business haha.

Thanks man. I think a big part of where you hear guys blowing their cars up on small pulleys is not doing it properly. Not enough cooling mods, supporting mods and bad tunes.

 

Thank you sir for the info as well. You were another I was hoping to shead some light haha.

 

go with the 2.6. when i ran that all i had was a dp, meth, and cai. the car ran great and the low end was fun. if i remember correctly i put down 281/255 with that setup, also had a 7400 redline but would shift around 7100.

 

someone should make a pulley that changes diameter with rpm. how cool would it be to have a 2.4" pulley in the lower rpms that changes to 2.8 by the end of the rev range?

 

Here is an M62 with a clutch drive on the snout

 

That's so sweet!

 

What's everyone running for meth/water mix? 50/50?

 

The MP90 I got Steve was a 4th gen. And the only diff between the 4th gen blowers and the 5th gen blowers are the coatings on the rotor packs. As far as efficiency there is no change between the two since they both still use the same 3 lobe 60* rotor pack.

 

With meth I would go to the 2.6. If I was still on the M62 I would have dropped down from my 2.7. I was running just a Cobra heat exchanger with that pulley and my intake temps never got above 145* on a 2-3 and half of 4th pull in the summer. That was also on E85 so of course my EGT's were nice and low, but like I said even intake temps werent bad. I say do it as long as your meth kit is in good operating order.

 

the best way to go slow is to read the internet... slap the smallest pulley you can on there the doesnt make the blower fly all to hell... you're probably WAY past the "official maximum rotor speed" anyways... If you blow it up its because you have a shitty tune... not because you picked up 2lbs of boost.

you have that... its your boost bypass valve, just set your boost percentage to be less up top...

 

thats still not a changing pulley size. and i have a lnf?