gotta drop a pulley size

 

shhhhiiiitttttt this is going to get my project rolling again..

on the search for a damn sc!

 

I'm about 90% Sure you can't make 10psi on an EJ25 with an M62.

That said.. NICE!!!
moar pictarz!

 

because?

Liter size of the motor or inefficiency of the M62?

Say I want 14 psi peak... should I keep trucking for a small M90 or am I trying to put a 35R on a oem block asking to run oem psi?

get my drift?

 

I'm getting a lot of pressure drop in the front mount intercooler. I know my motor can handle the psi so I'm gonna go with a bigger crank pulley and see if it increases any at all.

 

@bue: To put it simply...

1. after 10psi, the efficiency (pumping&temperature) of a roots blower really starts to plummet.
2. CFM Requirements for 10psi on a 2.5L motor exceeds max RPM of the M62.

Recall, I make 5psi with 12,000 RPM on the M62. The typical M62 is safe to 14k continuous, and usually safe to short bursts of 16k rpm. I'd have to run the #s, but I don't believe you can spin it fast enough, safely, to get 10psi. For that pressure, an M90 is by far the better choice. Lower RPMs on the SC, and better efficiency. Or.. go buy a Twin-Screw Blower!

 

I have been doing a lot of thinking and a couple long threads on the MR2 boards about this blower and the M90. This is a great thread and really shows how important it is to keep the pressure ratio as low as possible on these blowers.

@bue: To put it simply...

1. after 10psi, the efficiency (pumping&temperature) of a roots blower really starts to plummet.
2. CFM Requirements for 10psi on a 2.5L motor exceeds max RPM of the M62.

Recall, I make 5psi with 12,000 RPM on the M62. The typical M62 is safe to 14k continuous, and usually safe to short bursts of 16k rpm. I'd have to run the #s, but I don't believe you can spin it fast enough, safely, to get 10psi. For that pressure, an M90 is by far the better choice. Lower RPMs on the SC, and better efficiency. Or.. go buy a Twin-Screw Blower!

How are you calculating you hit 12k RPM on the blower? Just guessing from looking at the pics of the SC pulley in this thread if the M62 has a 4" diameter pulley you would need an 8" diameter crank pulley to double the RPMs.

On top of that just looking at the ratings and playing in the squirrel performance turbocalc for a minute at least on paper it looks like the M62 should be able to hit 10 PSI.
4th gen M62

According to Squirrel performance you should be able to hit about 300 CHP at 5600 RPM at 11 PSI and be flowing 422 CFM by redline. On top of that how often will you be sitting at WOT at redline? I don't imagine it would be the end of the world if you geared it to hit 15k RPM at redline. This should net you 500 CFM at 10 PSI. Since I don't think the stockish 2.5 would swallow that it would probably be more like 12 PSI and say maybe 450 CFM. That gives you a PR of 1.8 and leaves you still in a pretty decent area of the map.

Of course like I said this is all theoretical on paper so I would love to hear real world experience.

 

Thanks skidd.. pm sent.

 

I'll post up some more pictures once I make it back to Missouri. I'm in route to Virginia atm.

 

sounds good!!

didnt mean to go ot

 

Question for skidd. I currently have delta 2000 cams; my question is when you went back to your stock cams how much of a difference did it make in performance and what were the differences specifically?

 

In short, it went back to a stock idle/feel, but with moar power on boost (duh).
So, no more lumpy(ish) idle. I also want to say I gained perhaps 0.5psi more peak boost due to the decrease in overlap.

Was the difference huge? Nope. Was it noticeable? Yep.
Was it worth it? Yep, because I sold my 2k cams to someone on here who was willing to ship me his stock cams first. No downtime.

 

Got ya. I have a set of the stock cams already; does delta offer any type of regrinds for supercharger builds?

 

is that because the cams were not geared towards boost?

 

@gray: Yep. I didn't take them up on their offer, but they were suggesting that the 1500 (torque) grind cams would be great supercharged. Mainly due to the decrease in overlap. Something that a SC likes.

@bue: Yes. It's a bit of a black-art magic science, but one of the key things in a good supercharger cam is overlap. You don't wan very much of it. As apposed to NA cams, overlap can (and does) add top end power.

Obviously, there is more to cams than just overlap, duration and lift are important things to consider for a supercharger. But, on our cars we're not talking about the bleeding edge of power and performance. So, a stock, or a torque grind should be a good setup for an SC.

 

@gray: Yep. I didn't take them up on their offer, but they were suggesting that the 1500 (torque) grind cams would be great supercharged. Mainly due to the decrease in overlap. Something that a SC likes.

@bue: Yes. It's a bit of a black-art magic science, but one of the key things in a good supercharger cam is overlap. You don't wan very much of it. As apposed to NA cams, overlap can (and does) add top end power.

Obviously, there is more to cams than just overlap, duration and lift are important things to consider for a supercharger. But, on our cars we're not talking about the bleeding edge of power and performance. So, a stock, or a torque grind should be a good setup for an SC.

Can you back up what you are saying...

I have a turbo setup, T3/T4 .50 EBAY trim, (yes EBAY turbo) that loves overlap, it is sick lean when hitting 15 psi.

 

It's looking good! What spark plugs did you go with? I need to order my step colder plugs soon.

 

I used ngk's.

 

So it only cost you about $1000? How'd you do the tune?

 

Yeah it was somewhere between 1000 and 1300. I tuned it myself using romraider.

 

It looks great man!!! I'm glad to see those parts actually make it onto a car!

You're going to have to give me a ride in that thing if I ever manage to make it back to Rolla for more than a day.

 

thanks man, and will do. I thought I was gonna be in knoxville the other day but ended up not going. I'll def give you a ride when you're in the area.

 

Here is a video of it running for your enjoyment.

 

Awesome!! The very distinct sound of a blow-through fixed displacement supercharger!!

 

When I toggle the switch over to vacuum controlled it sounds completely different. You get the whine then the blow off. When it goes back into vacuum the supercharger turns itself off via the vacuum relay.

 

Shit! Sounds awesome man! Sounds like it must be balls of fun and the SC whine is just kick ass. Is it loud from the outside as well?

 

It's even louder from outside lol.

 

I would think that you could cut out quite a bit of the noise associated with the blow-thru design by switching your by pass valve/BOV to something with higher flow like the butterfly valves that are part of the newer Eaton designs.

I was looking into taking a small (38-42 mm) throttle body, attaching a 1" throw solenoid to the valve and hooking it up to the vacuum switch but bypassing the manual switch so it was always on. I had moved my battery into the trunk and was planning to locate it there and just stick a smaller air filter on it. It's sort of a backwards way of doing it but I think it would have worked well.

 

sounds good!

 

Uh... yeah... are you questioning my claims? Or just looking for info?

Supercharger tuning through cam selection and cam timing | Supercharger Performance and Engine Performance Parts

 

BAM!

-Billy Mays

 

Supercharged, 5lbs of boost 9:1 CR

Before the Supercharger, NA 9:1 CR

An increase of about 70wtq and 70whp.

For anyone who saw this post before I corrected it; I forgot to switch the data back over for the tire size from the winter tires.

 

I can't believe how different our torque curves are? :wtf:
I would have expected our setups to have very similar results.
I admit, I was hoping/expecting the near vertical curve I got.
But, I wonder why your curve is not the same?
@2k, mine shoots straight up at WOT, and only increases by about 25ftlbs until it starts to fall at 4k.
Yours increased by 100ftlbs between 2500 and 4500.
What gives?

 

Wow, how in the world did miss all these updates!

Awesome, awesome.

What exactly did you do with your PCV and breather lines to avoid boosting into the crank-case?

 

I Installed Grimmspeeds AOS and connected them to that. The check valve on the PCV would prevent pressure from going into the crankcase as far as I know anyway. I have one breather line connected to the AOS and it's for the return of the air after it's seperated from the oil.

I've never notice the dipstick popping up from excessive pressure in the crankcase.

 

I had my first hiccup on Friday. I was driving with the supercharger turned on and suddenly I lost power and could no longer hear the supercharger. Turns out I managed to break off the belt. Not exactly sure how that happened, but I got a new one and am back to boosting again.