Stroker/M90 Supercharger;)

S

seanyb505

NAXJA Forum User
Location
Simpsonville, SC
I've decided on building my stroker. I just bought connecting rods from ebay, and I'm thinking about whether I should wait until I have all the parts to buy a crap car until the new engine is road ready, or buy a junkyard engine to build while I drive the Jeep. So while combing my local U-Pulls, I found several candidate 4.0 engines. One place said 303 for an engine, and the place next to it said about 250. When I got my answers, I went rumaging cause you never know what cool stuff you'll find. Like and M90 supercharger off a 94 Tbird SC. SWEET!!!!!!!!!!!!!!!!!! I ran up to ask the price, it was nice, so i ran back to get it. about 20 minutes and 66 dollars later minus some piping, I owned a nicely rotating supercharger. Now I have some questions- I would want to get a 99 engine, but it's at the expensive place. Would a 91-96 lack anything I would want in a stroker? I have a 99 intake so it's not an issue. Second, how tall should the tent I'm pitching be over this SC? Would I be better off selling it or should I keep it and fab up some stuff for the stroker in the future. I love the wealth of information on this site, so I'll be asking questions and keeping you guys updated on my progress over the next 2 years or so


Im crapping my pants thinking there's a supercharger in my living room ready to do what ever I want it to!!!!!!!:laugh3:
 
seanyb505 said:
I've decided on building my stroker. I just bought connecting rods from ebay, and I'm thinking about whether I should wait until I have all the parts to buy a crap car until the new engine is road ready, or buy a junkyard engine to build while I drive the Jeep. So while combing my local U-Pulls, I found several candidate 4.0 engines. One place said 303 for an engine, and the place next to it said about 250. When I got my answers, I went rumaging cause you never know what cool stuff you'll find. Like and M90 supercharger off a 94 Tbird SC. SWEET!!!!!!!!!!!!!!!!!! I ran up to ask the price, it was nice, so i ran back to get it. about 20 minutes and 66 dollars later minus some piping, I owned a nicely rotating supercharger. Now I have some questions- I would want to get a 99 engine, but it's at the expensive place. Would a 91-96 lack anything I would want in a stroker? I have a 99 intake so it's not an issue. Second, how tall should the tent I'm pitching be over this SC? Would I be better off selling it or should I keep it and fab up some stuff for the stroker in the future. I love the wealth of information on this site, so I'll be asking questions and keeping you guys updated on my progress over the next 2 years or so


Im crapping my pants thinking there's a supercharger in my living room ready to do what ever I want it to!!!!!!!:laugh3:
Click to expand...


IN terms of the superhcarger the M90 unit is a direct mount unit as it mounts in place of the intake plenum. You will need some pretty slick fab work to fit it I would imagine. Not sure how much boost it will put out if you need to think about fuel delivery issues and tunability. You also cant intercool it and its going to get MIIIIIGHTY hot under the hood of your xj.
 
As of now Im thinking it will take the place of my AC unit. I havent used it in the last two years and I think i could make some sacrifices for some more fun. So for location and bracket fabbing Im not that concerned. An intercooler is something I would have to think about, and Im coming to the realization there is going to be a lot of piping. A new fuel pump would definately be necessary, and since it will be a stroker new injectors will be needed anyway, it's just a question of which ones. Is it necessary to mount the throttle body before the supercharger? XJ Armor has the SC in place of the AC and it looks like the TB stays on the intake manifold. No matter what happens, Im still stoked at this moment to even be building a stroker let alone have a SC involved.

I believe nothing is impossible at this point.
 
seanyb505 said:
As of now Im thinking it will take the place of my AC unit. I havent used it in the last two years and I think i could make some sacrifices for some more fun. So for location and bracket fabbing Im not that concerned. An intercooler is something I would have to think about, and Im coming to the realization there is going to be a lot of piping. A new fuel pump would definately be necessary, and since it will be a stroker new injectors will be needed anyway, it's just a question of which ones. Is it necessary to mount the throttle body before the supercharger? XJ Armor has the SC in place of the AC and it looks like the TB stays on the intake manifold. No matter what happens, Im still stoked at this moment to even be building a stroker let alone have a SC involved.

I believe nothing is impossible at this point.
Click to expand...

start researching.... your in over your head if you go at it now.

now only do you need new injectors, you need some sort of fuel management that understands boost, you also need something to pull timing as you boost. and OHHH so much more :D

(i have a turbo stroker in the works :))
 
That's why it's still sitting on my living room floor. If I didn'dt think I was in over my head I would have put it on already. I knew different higher flowing injectors would be necessary. I have no clue on where to even start looking for control of this system. The M90 has a bypass valve, to equalize pressure during non-boost times(I think? Correct me if I'm wrong). I am by no means educated on this topic. My roomates want me to put it on tonight with duct tape, I at least know this isn't a good idea and more work needs to be done. Which is why I would like to build a stroker that would accept pressure. If anyone wants to school me on this, I'm all ears to new info.
 
So I don't have any experiences with those kinds of superchargers, but it looks to me like you need a base of some type since you will be mounting the supercharger + base instead of the factory intake manifold? Is that correct.

Issue 2 and 3 are the pulley setup + tensioner, and then the air intake setup.

It can be done but someone is going to need make some brackets and work on the pulley setup. I think the fuel side of it would be the easiest part.

I had a custom centrifrugal supercharger setup on my 98 turbo'd formula, pics on page three of my car site:

http://psj.ls1tech.com/gallery/main.php?g2_view=core.ShowItem&g2_itemId=10&g2_page=3

So the big things I think you need to figure out, before you start screwing around, is where the blower needs to sit in order for the blower pulley to line up with whatever belt will be driving the supercharger. Phase 2 will be figuring out where the tensioner pulley will sit.

What you might want to do (assuming my comments about the intake manifold are right), is take a 94 t-bird intake and a stock jeep intake, and look at how you can weld the parts together.
 
As of now my plans are extemely preliminary. I know better than to try to put it randomly somewhere. I think the best place would be where the AC is, and i know a bracket will have to be built.
http://rides.webshots.com/album/325277378UlfWEd?start=12
Someone on here started to mount one, but I guess they ended up selling everything. I think I'm going to try to go off of what I see from the pictures. This isn't being built next month, or probably within this year. I need to research and find out everything I can to make this work.

Im not to worried about physical location of the blower, but more about the computer, and fuel system delivery. I have no idea what kinda of demands are going to be created. New injectors, FPR and higher pressure fuel pump are a must, Im just not sure where or what to start looking for.
Also I need to figure out how to either A.) Find a way to mount the 4.0 TB to the setup (bored, obviously) or B.) Find a way to make all the Jeep computer sensors fit the Tbird TB which mounts to the piping I have. Donor Tbird was a 93 btw.

Also it looks like all the electrical components will need to be moved from the passenger side of the engine bay, probably to the driver side, since the air intake(not manifold) will be moved to the passenger side.

Right now I know Im too far in over my head to start. The only way to fix that is to learn more. I dont see how this cant be possible with time, money and knowledge. I currently have more time than money and knowledge combined and Im in no hurry.

First things first though, the supercharger will not be put on my current 4.0 engine. I will be buying a junkyard engine and building it to a 4.7. Im hoping.

Any and all input is desired!
 
I know my compression will need to be lowered to make the engine more boost ready, will I need to plan ahead for lower compression pistons? If so, what characteristics will I need to look for. And does anyone know why Summit lists pistons as the same company but one with standard measurements and one with metric and the standard measurement cost 11 dollars more? Whats a good place for overbore piston rings? Ill be looking to go .030 or .060 depending on condition of the block. Will I need to take boost into account when purchasing piston rings?

Thank you in advance!
 
It's very encouraging to finally see people trying this with the M90. I had looked but it seemed that people didnt care or were going with turbos. I would, but I dont have a turbo I have a supercharger, and a Jeep. I work with what I have.
Keep me posted on any further info!
 
Ok so I'm looking at rod and main bearings. Not sure what to look for, I've read on here to get ARP 112-6001 rod bots, but what about bearings? Do I need rod bearings even if the rods have been reconditioned? If I do is there a specific brand/ part number I should be looking for? Ive seen Clevite part MS-1947P thrown around threads about building strokers, but are these for a specific year of block, or will they fit any 258 crank in any 4.0 block? I fully acknowledge my lack of intelligence or common sense on this subject and have come looking for help.
 
cnidy1230 said:
check ou this thread will help with some important specs you will need. My supercharger is getting close to complete and will post pics asap. my supercharger will be right on top of my intake since i hae a costum 5 inch cal induction hood. good luck!!! http://www.naxja.org/forum/showthread.php?t=103942
Click to expand...

I actually remember reading that thread a couple months ago, do you know if the clockwise rotation of the 4.0 serp belt drives the pulley in the right direction? I have not been able to confirm the nessecary spinning direction of the pulley on the blower. Im starting to draw up some designs to mount the M90 in place of the AC based on what Ive seen around. Also did you ever come up with a solution to an intercooler? And how wide is the highest part of the cowl induction hood? I know im going to need more room even if I swap the AC.
 
If the stock compression is 8.x:1 like I have read, that is already pretty boost friendly. I'd get something running with the stock engine and build a stroker on the side. With the stock engine I would run new valve springs since you'll need more spring pressure for the supercharged or turbocharged setup.
 
I thought about that, but I have too many miles on my stock engine for me to feel comfortable about supercharging it. I may do that if I get impatient with the stroker build, but I just figure Ill build the stroker with the blower in mind. I drew up some rough belt diagrams and a bracket to replace the AC.
 
Does anyone know if 30# Ford injectors will physically fit a 4.0? I chose 30# because thats what comes stock on the Super Coupe that I got the SC from. Is that too high or should I stick with just the 24# for the stroker?
 
Yes, 30# injectors will fit perfect on the Jeep 4.0 They will even use the same connector as pre-1999 4.0's I think 30# would be a good injector to run with Forced Induction. 24's are theoretically only practical for about 230hp. 30's are good for about 290 hp.
 
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Does anyone know the forumla to calcute boost or to calculate a supercharger rpm given the engine speed and crankshaft pulley diameter? I know my SC make around 11 psi on the 3.8 V6 it came from, but I think since it was smaller and probly turning higher rpm I wont be getting near that. Id like to know what to plan for.
Thanks in advance!
 
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