Going to look into a custom FEAD setup, might be good insight for those LSJ owners who desperately want to delete their A/C compressor. The LSJ tensioner setup is just too dang expensive and I don't need A/C because a gigantic tilted radiator took over the front end.

Here is the latest concept, I am running an LE5 head so there are bolt provisions for the factory lift bracket I can take advantage of:

*picture is from strat81 in his thread here: http://www.j-body.org/forums/read.ph...6&t=480866&p=3

 

Hey Slowbalt, I just realized I am running an underdrive setup (ATI balancer), so a 3.2" pulley is just about equivilent to a 3.6" pulley with the stock damper. I'm going to keep this 3.2 on and see what happens.

 

As long as the belt doesnt slip on the alternator I dont see why that wouldnt work.

A 3.6 pulley will work but might create unwanted heat. The stock pulley is 3.35” I believe if you have one of those. Just keep this efficiency map in mind when sizing the pulley.

 

stock is 6.5" i believe, not 6.25

 

Thanks for clarifying, I was inferring the stock diameter going off of ATI specs 5.5" / 88% = 6.25 My logic is 12% underdrive so 88% times 6.25 = 5.5

 

Waiting on a 6-rib alternator pulley and bought a bunch of belts, almost there:

More pulley development/fab pictures here: http://www.kappaperformance.com/foru...1551.msg195302

 

Whats with the idler pullies?

 

did you get the alt pulley from ottp? they have an aluminum alternator pulley for a reasonable price

 

LSJ belt system on my specific application requires:
1) A/C compressor installed, would be dead weight I have a huge tilted race radiator custom mounted
2) LSJ Alternator, $$$
3) LSJ tensioner and idler, $$$
4) LSJ silly double ribbed belt, $

Too many $$$ plus dead weight, so I went custom idlers to custom route a standard belt

 

It's a generic bolt-on style alternator pulley, $15 + shipping...if it doesn't work I've got a lathe. The OTTP pulley is pretty slick though.

 

You can spin the stock alternator backwards no problem. I also use the LE5 belt tensioner with the LSJ idler pulley/bracket just riding against the alternator.

 

Do you have a picture of your setup? LSJ idler bolts up where the LE5 tensioner goes see below:

 

Sorry, i use the LE5 tensioner with the LSJ tensioner pulley. I dont have the strut for the tensioner so the bracket for the pulley just flops down and sits on the alternator.

 

Twincharger specific poormans bypass controller:


*based on speculation, I have no empirical data to show what the boost pressure is after the TC and after the SC.

 

Someone suggested looking at controlling the BPV like OEM, but I don't think it will work after drawing out some diagrams. I am cautious about saying my initial idea will work but conceptually it might so I'll integrate it. I will instrument pressures and see what is happening. I'd like to get a position sensor on the BPV, string pots are so expensive and my 3D printer is down, maybe a limit switch is a simple way to see when it's in the closed position for now.

 

I always just had mine hooked up like stock. Closed in boost and open in vacuum. Even bypassing, youre still using engine power to spin the blower, but now youre not using any of the work to add airflow.


My prefer the KISS approach, but you may do as you wish.

 

I am already generating ridiculous amounts of heat with the turbo only setup, so I am stuck on making the BPV open when the turbo is spooled on the twincharger. Nothing wrong with KISS, in fact I'll run it like your setup for first fire and drive of the car then play with my idea!

Dave with DDM provided some feedback early on, this is what he said about his experience twincharging with the M62 (TL;DR about +30 hp from bypassing):

On all of the twincharged Atom's we have done we used the internal bypass on the M62 instead of doing a custom throttle body setup. It is much easier and simpler to do this and you are mainly just trying to equalize the pressure delta across rotors of the supercharger. Once you have no pressure delta across the rotors, the "work" being done by the supercharger substantially decreases and in our testing was good for around 30hp. To control our setup we just use a 2nd boost controller that references off of the intake feeding the supercharger, once that incoming air becomes pressurized higher than the set point, the "wastegate" bypass on the supercharger starts to open. That provided a nice smooth drivable transition once it was setup and controlling everything correctly. We have done a bunch of these twincharged Atom's now, if you have any direct questions, feel free to shoot an email to me - Dave@ddmworks.com. Hope that helps.

 

Interesting information there. Thanks for sharing.

 

M62 transplant onto an LE5 complete (deleted A/C compressor). I installed a 6-rib alternator pulley, universal bolt-on style pulley ($15). I needed to lathe a step for clearance otherwise the axial offset distance was standard.

 

I like that

 

I like that too. It looks like it was meant to be there.

 

Work-In-Progress


Surge tank fuel system:

 

I decided to spray the meth before the throttle body to avoid needing a solenoid due to low pressure (vacuum), so put another nozzle next to the original. In addition, since I plan to run the M62 bypass under WOT, I hypothesize that the meth mixture will be more consistent. Port injection is the final solution.

 

I just use a check valve with 25psi cracking pressure to prevent vacuum from causing meth to flow through my nozzles.