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Project Shoehorn - M90 into a 4.0L

Good now, better later... Stand by that dial.

OK. So, nobody is going to get a Radio reference... Sorry about that.

But have you all noticed that there is room for an intercooler?
 
O-Gauge Steamer said:
Good now, better later... Stand by that dial.

OK. So, nobody is going to get a Radio reference... Sorry about that.

But have you all noticed that there is room for an intercooler?
Click to expand...

By the battery area?
 
Daggone this thing is fun and I'm not even done with final stuff yet. Going down the highway easily keeping up with traffic, then when I have to pass I just give it a little, the bypass valve closes, and by-bye.
 
Fair Warning. This is habit forming.

Once exposed to a supercharge vehicle, you will never, ever, want to drive a non boosted vehicle again. If you have more than one vehicle in the garage, you will start wondering just how difficult can it be to add a supercharger to that vehicle as well.

You have been warned.
 
Too late. I've already been wondering what it would take to swap an STI motor into my wife's Subaru Legacy that is NA. (Budgeting for at least 2-3 speeding tickets a year by her has to be included in the price planning)
 
You know... Subis did come from the Factory with Turbochargers... They have different cylinder heads as well as a few other part changes but, it is a bolt on... Looked into it for the Kid's Subi.
 
Happened to stop by my local Advance today to ask about vacuum fittings since I'm trying to shorten up my MAP sensor line. The floor guy couldn't quite see what I was asking for so I showed him. When I opened my hood the guy about crapped himself. He was telling random people walking by to look at it, taking pictures. Hilarious.
 
So a lot's been going on.

The short version? For performance critical parts, NEVER buy used, or if you do plan to have it rebuilt.

Here's the long version. While I got everything in and running, the overall boost level was not was was calculated. All numbers pointed to around 8-9 PSI of boost, but I wasn't seeing it. A run test with the compressor independently seemed to indicate it was functioning correctly. Went back and ran some numbers for drive ratios to compare boost numbers against other engines using the M90. It seemed as though it simply wasn't spinning fast enough so I pulled the compressor again and installed a 2.8" pulley. I got the approx. 2 PSI I expected to get but still not what I would expect overall. So I did a residual pressure test to see if I was getting losses in my intake and I was, so I replaced the ribbed intake tube with a much shorter and smooth-walled intake setup. Marginal improvement at best. It does develop boost, but not the level I expected.

So at this point all indicators, compared against other comparable setups, point to my M90 being faulty and simply not pumping enough air. This is likely due to too large of a tolerance between the rotors themselves and between the rotors and the housing allowing air to slip by instead of being pushed. I did not have the compressor professionally rebuilt when I got it. I am likely going to need to rebuild or completely replace the unit. Nothing is solid yet as I still have a few things to try but it is highly likely.

At least my engine compartment looks extra clean now that I redid the intake:



Just to be clear though - the design is solid, I just sabotaged myself from reaching maximum performance because I cheaped out on parts at the beginning. I got burned on pretty much every part that I bought used on this build.
 
Man, that is some really crummy luck.

So when are you going to take out the tube over the valve cover and replace it with an intercooler in front of the radiator+AC condenser? :firedevil
 
IMO, what is happening here is why I recommend professional rebuilds of the compressor prior to installation. With the rebuild, you get a couple of guarantees. First one being that the compressor will actually pump at the rated output and the second one is the peace of mind you get knowing that all of the bearings and seals are solid. Nothing can ruin your day faster than a compressor failure when you are away from home. It is a Show Stopping Event.

Plus... Places like https://jonbondperformance.com/ offer a service where they can add a coating to the case and rotors that improves the sealing over stock. Some OEM manufacturers (Jaguar comes to mind) specify the coating on their OEM parts and, as a result, get remarkable amounts of boost. I believe that the Jaguar delivers 13 pounds of boost to their 4.0 Litre inline 6. Intercooled of course... The aftermarket for Jaguar does offer pulleys that take the Jag to 17 pounds of boost. An M90 feeding a 4.0 Litre...

To my way of thinking, spending the cash up front beats spending it in a crisis situation.

This is not a crisis situation, it is just that the compressor is not living up to it's potential. This is, trust me as I have gazed upon it's undeniable beauty, a very clean installation indeed. And it does have the potential for so much more as the Harmonic Balancer can be changed out from the 6.375" stock diameter to the 6.72" performance version. This makes for a substantial compressor speed change which, obviously, directly translates into increased boost.

One of the nice things about superchargers is that you can make mechanical changes that are, in of themselves, relatively inexpensive and easy to perform that have the potential to completely alter the performance to the vehicle that compressor is fitted.
 
YELLAHEEP said:
Um.....Ahem.... Not EVERY part.

;)
Click to expand...

You are correct, not every used part had issues. Just every part of the compressor, pretty much all my gauges, and a TPS (I don't know where it came from, but one had issues).

O-Gauge Steamer said:
This is not a crisis situation, it is just that the compressor is not living up to it's potential.
Click to expand...

Correct. By all the numbers I should be getting at least double the pressures I'm seeing now. It's better than stock, but not enough to write home about (yet).
 
IMO, it is a matter of "pay me now or, pay me later". This is the basic issue with used parts. They will have issues earlier. But I will be the very first to admit that it is a hard sell.......
 
I'm glad you didn't keep that dryer tubing, it was really giving me a "turd in the punch bowl" vibe :roflmao:
 
Nothing funny sounding that I or OGS could notice.

There was a some scoring on the housing walls and rotor edges. Looked like it might have ingested some debris at some point. Not sure about main bearings. I replaced the tail bearings before it went in.
 
This compressor is so quiet that I can not hear it at all. Given that I "enjoy" about a 45% hearing loss this may not mean much but... I can hear my compressor at all times.

Makes a very nice whirly noise. The sort of sound one can get to like very quickly...
 
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