3800 M90 Build

Ok the cats out the bag!!im going supercharged .its a 3800 gm m90.i need lots of help as im a nos guy.for starters my list of mods is in my signature.the guy im buying it from ran it on a stock tuned motor at 3psi.first question is what is the "safe" limit to run boost at?i know it is not ideal but i have a wide band O2 and will be doing tuning very soon.i also will be trying to have my company make a new lower intake mounting bracket on the cnc machine and have it taped for nos/water meth injectors/spray bars.i will also be getting a p+p unit from 3800 performance and stepping down on the pulley to try and run 8-10psi.what size injectors should i run for that?which fuel pump should i run?any suggestions on tuning?i was going to go mega squirt but i see sct has a new chip out,any suggestions?


DONE
ported and polished gm 3800 gen 2 m90
Water to air intercooled
port matched 76mm inlet and intake tube
mustang 75mm race tb
90mm maf
36lb injectors
255 fuel pump
sct 5bank dyno tuned
2.7" pulley 10lbs of boost!!

dyno run,these was the last two pulls with the 2.7 and the alternator was bad.turn your volume down!!


and a 3.25 pull and think my rev is still set to 5000 in this one

 

[rocket 5979]

Yep totally understand that.thats what i was saying,he had restrictions on inlet side and i less on output side so may equal out to what he was getting.i think 4lbs was real low for pulley size.i seen others on here make 45 on the 3.8 pulley.i have 3.2 on sc and im having someone measure crank right now i also have 10.5:1 compression so each lb of boost will make more hp or you think that 18-20hp per lb of boost will be close,its going to have very little restrictions also,everything is ported and inlet side shouldnt be restricting at all.

If I were you I would figure for 15-17rwhp. Twin screws and modern TVS make in the 18+ area but I don't usually see many Eaton's doing it according to my recollection. Use 15rwhp per psi and if you get more then be extra happy.

 

[jd4242]

If I were you I would figure for 15-17rwhp. Twin screws and modern TVS make in the 18+ area but I don't usually see many Eaton's doing it according to my recollection. Use 15rwhp per psi and if you get more then be extra happy.

HOLLY MOTHER OF JESUS! !i would be super happy with 10hp!!im totally new to fi so that fact that i wann run 8-10 would mean a 120ish hp.i dont see that as true to the ground as im 4x4 but if i break 300hp after tune i would do a flip!! Working on getting that crank pulleys size now.

 

[jd4242]

Yes it will get you close.

To figure pulley size from required boost level:

Step 1: ((14.7+Boost) / 14.7) x (engine liters / 2)) / Supercharger Size liters = Theoretical Pully Ratio*

*Assuming "0" inlet losses and 6.5" crank pulley.
For 6 psi boost with a 1.5L supercharger on a 5.0 engine: ((14.7+6) / 14.7) x (5.0/2))/ 1.5= 2.34 ratio

Step2: Then divide the pulley ratio(2.34) into the crankshaft pulley size (6.5") to determine supercharger pulley size (2.77").





The Eaton M90 displaces 90ci of air per rotation so that converted to liters would be 1.5 liters.

Ok may have done this wrong but came up with 5.15lbs of boost.crank is 6"sc is 3.2.so he was lossing some,double check also on those other people running a m90 and it was 5lbs with a 3.4. So think the math is pretty close

 

[rocket 5979]

Ok may have done this wrong but came up with 5.15lbs of boost.crank is 6"sc is 3.2.so he was lossing some,double check also on those other people running a m90 and it was 5lbs with a 3.4. So think the math is pretty close

Pulley ratio 6.0" / 3.2" = 1.875 ratio

Theoretical boost = (charger size in liters x pulley ratio) / (engine L / 2) x 14.7 - 14.7

(1.5 x 1.875) / (4.0 / 2) x 14.7 - 14.7 = 5.97 lbs boost

Based on that you can estimate a rough gain of 90rwhp give or take. Of course how aggressive or how conservative the tune is, engine flow efficiency, camshaft specs, supercharger inlet flow efficiency, drivetrain losses, etc will play a sizeable role in determining your total number.

 

[jd4242]

Pulley ratio 6.0" / 3.2" = 1.875 ratio

Theoretical boost = (charger size in liters x pulley ratio) / (engine L / 2) x 14.7 - 14.7

(1.5 x 1.875) / (4.0 / 2) x 14.7 - 14.7 = 5.97 lbs boost

Based on that you can estimate a rough gain of 90rwhp give or take. Of course how aggressive or how conservative the tune is, engine flow efficiency, camshaft specs, supercharger inlet flow efficiency, drivetrain losses, etc will play a sizeable role in determining your total number.

Oo ok see what i did wrong.so a 2.7 will give me 9.5 or a 2.8 will give me 8.8?

 

[rocket 5979]

Oo ok see what i did wrong.so a 2.7 will give me 9.5 or a 2.8 will give me 8.8?

2.7" gives 9.8psi and 2.8" gives 8.9psi with stock crank pulley, M90, on 4.0.

 

[jd4242]

2.7" gives 9.8psi and 2.8" gives 8.9psi with stock crank pulley, M90, on 4.0.

Sweet again thanks alot!im going to start with the 3.2 and after i get tune go to 2.7.i wanna have two tunes,like a 3.5ish tune for long drives and stuff and a 2.7 for trails and street. think 9lbs-ish will be about max safe for my motor

 

[jd4242]

I have a 3.8 and 3.2 but they are press on.so going to modular after i see what the 3.2 will do.but i have alot of p+p and bored over.20 and 10.5 so dont really know whats safe.but ohv blocks are dime a dozen so if i blow it a stroker and copper gaskets/orings will go in and the fun will start

 

[Wills05xlt4x4]

Im ready for a ride...

 

[blk mk8]

Cool build

 

[jd4242]

well little update.put the sohc pan on last weekend and found out it does not clear the engine crossmember.so for the time being i shimmed the motor and trans up 3/4 of an inch.im going to make solid motor and trans mounts that are an inch taller than stock.ive been wanting to get ride of that rubber crap for awile now.the pan clears now but wouldnt feel safe with as much as that motor rocks around!!for the trans im just using a 3"x3" square tube and for the engine im making them out of 4"x8" rectangular tube.of course there will be more to it than that.im waiting on the intake tube and steel tubing to come in so its going to be a week or two before i get back to this.i also got my new fan in and it fits on the radiator like a glove,should make a HUGE difference over the HHR!!this weekend i think ill try and put the new injectors in and new fuel pump.not much more i can do till i get the metal inhere is a pic of the fan,still have to make brackets but thats a piece of cake.

 

[Dono]

That fans a monster!
yup, no cooling issues, that for sure.

 

[jd4242]

That fans a monster!
yup, no cooling issues, that for sure.

yea it should really work well,said to pull 4300cfmsits alittle thicker but i run a custom manual rad so i dont think ill even have to trim it.its a two speed but think im just going to wire it up to kick on high all the time.think im going to change my tstat out to a lower one also and have the fans kick on alittle earlier.side note got the metal for my mounts now,just need to weld them up

 

[Dono]

How are you handling the IAC? I need to spend more time understanding where each hole goes in the intake. The iac has two holes, really close together. I'm confused (again).

 

[jd4242]

How are you handling the IAC? I need to spend more time understanding where each hole goes in the intake. The iac has two holes, really close together. I'm confused (again).

i dont know how yours will work.im using a 75mm mustang tb and the aic is built into it.stock ones on our truck is on the side of the upper manifold

 

[Dono]

I'll have to start a build thread right away. My Manifold came from rpcaster, and I have more questions. Im going to have to adapt this to work on my ohv (Just the ports required). I don't see a spot for the iac in the manifold, so I'm going to have to fabricate something.

I am impressed with the workmanship, lets hope that I can do a nice job of fabricating, and don't make a mess of things.

 

[jd4242]

I'll have to start a build thread right away. My Manifold came from rpcaster, and I have more questions. Im going to have to adapt this to work on my ohv (Just the ports required). I don't see a spot for the iac in the manifold, so I'm going to have to fabricate something.

I am impressed with the workmanship, lets hope that I can do a nice job of fabricating, and don't make a mess of things.

its a ohv lower manifold right and has the manifold tube where the tb mounts right?send me a pm with some pics

 

[Dono]

I started a build thread. It's time.

 

[jd4242]

well little updates.got my exhaust off and test fitted the cats i made and they fit perfect!!! also got my trans mount pulled and mocked up,it fits perfectmy stock mount was trashed and its not even a year old,hoping my front ones aren't trashed alsoglobal sent me a invoice for the cancellation and cost of the new intake pipe,it was $50 plus shipping witch the quote was $19,SO A $70 3 FOOT PIECE OF PIPE!!!:thumbdwn: AND STILL HAVE TO PAY TO HAVE IT CUT AND WELDEDAny rate tomorrow or Sunday i think ill finish the trans mount,drop the tank and try to get the injectors.here are some pics

and the pan,last pic you can see where it was hitting,it clears now but is going up another 1/2 inch

the material im making the mounts out of,top two is engine and bottom is trans.the engine ones still need to be cut down to an angle and plated

like this but smaller

 

[rocket 5979]

global sent me a invoice for the cancellation and cost of the new intake pipe,it was $50 plus shipping witch the quote was $19,SO A $70 3 FOOT PIECE OF PIPE!!!:thumbdwn:

I could see a $19 quote for a run of the mill piece of mandrel bent pipe. But when they have to set up a single run to bend a custom angle then the price skyrockets due to the added setup costs.