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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!!;)
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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
 



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Hey man, replied to your boost question in the other supercharger thread you posted in.

I think you'd be good to go with 24# injectors or maybe a little higher.

For the fuel pump just use a Walbro 190 LPH one for a 1991-1994 Mustang GT 5.0. It will fit right up.

You should be able to run up to 9psi of boost with the water methanol and little to no timing retard. The NOS shot you'll have to play around with but I'd keep it small...like 50. Nice thing with running the NOS with water/meth is you can spray it dry since the meth acts as fuel.
 






Yea saw it right as i was sending you a pm.you said you ran 24lbs injectors with no tune?how?yea was going to keep the shot real small and use water meth a the gas side of it.but i heard you wouldn't need that till after 10psi.i was thinking i just back the timing down and use just a small shot of water meth at wot for dd
 






Yea saw it right as i was sending you a pm.you said you ran 24lbs injectors with no tune?how?yea was going to keep the shot real small and use water meth a the gas side of it.but i heard you wouldn't need that till after 10psi.i was thinking i just back the timing down and use just a small shot of water meth at wot for dd

Yep, 24# injectors with no tune. Like I said the computer was pulling a lot of timing on its own so that kept it from leaning out too much. It also kept it from really making a lot of power. Even if all the timing was back in I think 24# would have been fine though.

For your water/meth you could also run a hobbs switch so that it will kick on at a certain level of boost. if you put the water/meth on a WOT switch that might work too but with the type of blower you are going to run you can build a lot of boost even at part throttle and that could cause knocking. So it's a good idea to make the water meth kick on at a certain boost level. not too low...maybe starting around 4-5 psi. That will also guarantee that it's already spraying when the nos kicks on.
 






I thought it had to be tuned when bigger injectors were put in.Aww good point,that does sound safer.so with just 3lbs of boost right now what do you think i need to do before a tune?i kindof wanna put it on till i can afford everything to go higher in boost?
 






O i run tr6 plugs now,one step cooler than stock
 






I thought it had to be tuned when bigger injectors were put in.Aww good point,that does sound safer.so with just 3lbs of boost right now what do you think i need to do before a tune?i kindof wanna put it on till i can afford everything to go higher in boost?

I had a Pro-M maf that was tuned for those injectors so they would have the right pulse width.

You should at least go ahead and get the fuel pump done right now so that when the time comes to crank up the boost you'll have enough fuel pressure at the rail.

If it's only 3psi then you might be OK with just the fuel pump but put a boost guage in so you can at least know how much boost the blower is actually putting out.

Main thing is to listen really carefully for pinging or knocking under load and if you have any then back off. Keep an eye your plugs to make sure it's not too lean.

Then when you get your megasquirt in and your bigger injectors you can throw the small pulley on that thing and have some fun
 






O ok gotca .i got the wide band o2&gauge and will be getting a boost gauge.yea i will probably pull the timing advance plug atleast till i tune it to be safe.the high compression with 3lbs may turn out to be alot more risk for detonation .ill let some others chime in before i do anything.im thinking 30lbs so if i ever wanna go big i can;)
 






sub!
Looking forward to this.
Where does the wideband o2 sensor mount?

should have searched:Exhaust, before the first cat. i guess drill a hole in the exhaust pipe and weld a bung.
 






I have headers so it has a hole already.i only have one right now and its mounted where your riverside o2 is.i plan on adding another one so i can read both banks as im only reading one right now.for a first gen we only have one o2 and it mounts in front the cat.the wide band i added.is there a vehicle that came stock with 24 or 30lb injectors ?
 






I was waiting for that question to be answered. Any info I have found on injectors doesn't say how many # they are. They rate in something else like gallons/minute (Or something like that).
I might be ok for injectors as I bought the wrong ones off ebay. They fit, but I kept getting codes that both banks were rich. If I could figure out what they were I just might have ones that will work for me already.

I'm hoping one of the experts can chime in on this.
 






is there a vehicle that came stock with 24 or 30lb injectors ?

Its been a very long time but I think ordered mustang ones. Not sure if they were OEM though. the guys at RPS could probably answer your question on the injectors for sure.
 






Stock for us is 19 and mustangs come in 19&21 &i believe the gt and lightnings came with 24,believe.yea need an expert to chime in on how much boost each size will handle.also if 24 will work up to say 15lbs of boost can i just get the electronics from a maf that's programmed for that size?
 


















Just slightly lean gives more power, but you might be shopping for new pistons. I agree, slightly rich is the way to go to keep things a bit cooler with that kind of boost/compression.

I also read somewhere that going too large will create a rougher idle. If you go too large, doesn't that mean you will just have to tune the injector pulse width down? I'm betting that someone will chime in that the 24's are lots and the pulse width can be turned up on them. Henson performance will be able to answer that easily I think.
 






Im sure 24 would work but be close to the 80% cycle .i think it would be best to turn down 30lbs then if i wanna turn up boost they still would be capable.
 















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So whats the order of operations? Wideband o2, fuel pump, injectors, TUNE, and then add the M90?

I thought you would need a tune after the M90 was installed.

Your truck is going to be insane.
 






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