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BIG motor help ? . . warning its a LOT to read !

sweetk30

sweetk30

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so its not a gm but a ford i am helping with .

331 stroker at 425hp/400ft lb at 9.75:1 static comp ratio . 58cc dart pro 1 heads . full roller engine . scat cast crank . other goody parts . here is the engine page . https://www.tristarengines.com/perf...s-retro-fit-hydraulic-roller-camshaft-lifters

he has this to drop on it . http://www.tpsmotorsports.com/kenne...-1986-1993-5-0l-mustang-supercharger-kit.html

using this program calculator https://www.rbracing-rsr.com/compression.htm and knowing he got a 6 / 9 / 12 psi pulley combo for it i played with the #'s and fond a BIG problem .

static comp ratio on new engine is 9.75:1 with the pistons and 58cc heads .
all info specs are at 1k feet above sea level in the calculator.
6...psi = 13.53:1
9...psi = 15.52:1
12 psi = 17.51:1

if we drop to a more normal static for a blower engine that i could see surviving i picked 8.50:1 just to play with the #'s and here is what i got .
6...psi = 11.77:1
9...psi = 13.50:1
12 psi = 15.24:1

also keep in mind this engine was sold as a N/A engine so ring gaps and suck parts are NOT set up for the big boost #'s i see if its going to run and live .

he was talking with tri star engines and told them he was going to put this blower on it and run 6 or 9psi a lot of the time and maybe toss on the 12 psi for fun ( but looks like now at this time ) . they didnt even install a blower cam that is offered for the maker they used and super close to the specs of the one in it now . also the one in it now is 110* LSA and the car is a 87 mustang with stock efi and crane cams fireball box and coil unit .

i just dont see the engine holding up at all to this combo of parts as it sits . i told him i dont play with motors but my own so i am NOT tearing in to this engine to swap stuff / fix stuff / bla bla bla . . . .and this would also void his warranty .

i told him also stock 5.0 blocks are limited to around 550 hp N/A or less on blower setups and strokers . he was thinking stud / main girdle but the builder talked him out of it . . ..

next was the parts LMR sold him for the clutch kit . the 28oz ALUMINUM flywheel is sfi spec and has grd 8 bolts and lockwashers in a ZIP LOCK BAG . . :eek::confused:https://lmr.com/item/SPC-SF82A/Spec-Mustang-Aluminum-Flywheel-28oz-86-95-SF82A

the clutch kit was sold to him as holding up to the power of the new engine and blower . . . i call bull crap this motor if running now would make more than the 567 ft lb torque spec max it shows . https://lmr.com/item/SPC-SF482/Spec-Stage-2-Clutch-Mustang-86-01 its also NOT sfi rated and the pressure plate hardware has socket head allen 12.9 bolts and the thinnest crappy looking lockwashers .

he has a tremec t-56 6 speed in it already when i purchased the car . so we dont know if its built or just a std kit trans . it has some tags / stickers on it i will read up and find info on them . otherwise who knows if the t-56 will hold this much power and survive .

he is doing the car for street and 1/4 mile fun . tubular K-member conversion front end and coil overs . man rack conversion . has bigger brakes and 5 lug swap kit front and rear on the ford 8.8" rear .

most all the stuff he has got is from LMR and i am NOT impressed . there has been ZERO directions given and it all looks like cheeper china grade import junk to me . but i am not sure since its all ford .

i know this is a lot to read . but if any real more in depth engine guys can help we would be greatfull . . . . i am just the install guy and he picked all this stuff and it just showed up or i would have directed him to a better engine before he got this far down the rabbit hole.

tagged in already @Bent77 @Justin V @Shawn maybe @beags86 and if he is lurking anymore @4X4HIGH
 
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Nearly 10:1 compression isn't bad if he's running e85 and the pistons are forged and the rotating assembly appropriately built.

That's kinda sad to hear about LMR. It's been a while since I was into mustangs but when I was they were the top dog.
 
engine is forged pistions . but the whole engine was built for carb by the looks of it . NOT boost and at the levels he wants to play with .ring gap i am sure would need fixed / heads with bigger chambers to drop the static comp ratio for more tame boost level #'s . and a boost cam would be better i think .

E85 is not super comon in my area that i have noticed but i dont look . i did tell him this might be a option but bigger injectors will be required .

LMR stuff i got so far seems o.k. but like i said no directions and some hardware looks super cheep for such important parts .
 
I’ve seen a stock 5.0 block crack at 650 hp level with nitrous.
E85 is a great option if available.

that’s a lot of compression for that motor
 
Kinda sorta same thing, but the whipple in my Yukon is for a STOCK engine, they are 9.4, and can put out 6psi boost, and more if change pully. Cast pistons, prolly cast crank. Even 12 pounds boost isn't that much.
 
He might be getting close the limits on that 302 block. You are right. 550hp is the most you want to push. I have seen 302 blocks split at 450 and I have seen same blocks last at 550hp. Depends alot on the tune as well. Alum flywheels are hit or miss and can really suck in in stop and go traffic. You really want a heavy flywheel to help clutch engagement. Definitely should be SFI. The clutch should be something that will handle the past the estimated torque/hp. Most single disks can't. Compression might be a little high on pump gas but still doable. High octane or E85 if possible even if he has to go get a 55 barrel drum. E85 is SO forgiving. I was able to run 40psi in a 4 banger and make 1003whp on E85. It also help cool the intake charge which is crucial with forced induction. Worried about the cast crank too. If he keeps the boost to minimum and the timing mild, it might just live. The other thing he will have to deal with is cooling. Huge radiator and good fans is a must.
 
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so he has a aluminum aftermarket rad now and brand new 2 fan setup with shroud for the install . has adjustable temp on/off switch / relay combo .

he wants more street time i think and drive to the trac or trailer it he can do both the the 6 speed and has trailer .

not a ton of big city stop/go traffic around here . but there is some .

what do you guys think is a safe static comp ratio to start with on the blower he has for it ?
do you think he is safe with the ring gaps if it was set up good for N/A use and now getting a blower ?

i just dont wana see this whole setup go BOOM and him loose a lot of cash and time .
 
I'd call the engine builder and see what their ring gaps are and see if's within specs for forced induction. Should be ok but double check.

What fuel? If pump premium gas then start with 6 psi and maybe invest in a knock alert and run very low timing then go up a little and see how it does. Is he doing EFI? Also is he doing head studs? I'd suggest the ARP L19 studs and a good HG for boosted engines. Felpro usually does well with boost.

Now... if he can get his hands on some E85 then he could easily run higher boost, smaller pulley. E85 is like 108 octane. BUT... you need more fuel which means larger injectors or carb and much larger fuel pump. The larger Walbro can flow 124 gph/470 lph and easily keep up but its only for EFI pressure, not carb. Regardless you will need a pump that will keep up with fuel demands.

Some good articles like this that talk about it
https://www.onallcylinders.com/2018...i-put-a-blower-on-a-383-with-101-compression/
 
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For that kind of money,I would be getting an all aluminum 460hp,425 ft-lb torque crate Coyote.

Why a 331" as opposed to a 347" stroked.
 
One more thing to check on. Aviation fuel. Should be around 100 octane.

Also any octane booster in a bottle is useless. Stay away from those
 
Shawn said:
One more thing to check on. Aviation fuel. Should be around 100 octane.

Also any octane booster in a bottle is useless. Stay away from those
Click to expand...

cant use av gas . its got lead in it . kills o2 sensors and cats . he only has o2 sensors tho .
 
Following!this seems like a very interesting thread
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Today’s aviation fuel is actually pretty low lead content from my understanding. We would mix it 50/50 back years ago with 93 octane. With good results. I would think that it would be ok on o2sensors for at least 10-20,000 miles....

I would definitely check ring end gaps before boosting it! Most built n/a motors that I’ve seen and built have pretty tight end gaps.

i may have missed it, but what fi setup? Can he go flex fuel? That makes buying a drum of e85 a lot more feasible when you can just mix in 5-10 gallons and the computer automatically tunes for it.....

I wouldn’t be scared to run 5-6psi on 9.5-10:1 compression with modest timing and correctly gapped rings.

my ls3 427 stroker build I’m working on is 10.5:1 compression and going with a 4.5 whipple and e85.... I think I can get away with 12-15 pounds of boost and with the flex fuel sensor if i need to run 93 the computer will compensate for it
 
i work aviation and its called 100 low lead fuel . as to specific levels i have no clue .

its stock 87 mustang efi for a 5.0 .

we are looking in to the e85 fuel supply in our area before we go this direction .

he is calling the super charger place monday and talking with them and then the engine builder and try and get a solid answer from both sides .
 
I have seen John Force get away with running a little over 9:1 compression with a blower, but that was with Austin Coil tuning the engine, and a large bank account. It seems like this guy did not do his homework on this engine. Tell him to try a turbo-charger instead of a super charger.
 
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