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Discussion Starter #1
As many of you know Mundy from Miami bought my old TT kit, with T-25s he made ~300/365 @ 8psi. He got some bigger 16G turbos and I tuned the car today.

The first run at 8psi actually made less power than the old turbos...the new turbos spooled slower, they weren't building as much boost as quickly.

We kept creaping the boost up, finally hit 13.5psi and decided it was time to stop and try the cutout. With it open the car made 14psi (same wastegate settings).

Ambient 85F
Engine coolant 170F
Peak Air temp after IC 138F
93 octane (12:1 a/f and conservative timing)
No nitrous
Completely stock JY 3.8 longblock
About 15min of cooldown



I see some possible tweaks but the car is doing very well as-is.
 

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I dunno about Ford 3.8's in particular, but I could run 12-13 psi of boost in my 2.2L MoPar all day long, pushing a heavy minivan about. No intercooler either. I put thousands of miles on it like that. That was about the safe limit for unintercooled boost on that particular engine.

Much past that and an intercooler was needed as well as more fuel beyond what the computer could provide, or you paid the price. About 20 psi was the safe limit for an intercooled and added fuel but otherwise stock engine. Above that and you really should go with forged pistons.

Steve
 

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well, the 2.2's also have a compression ratio of 8.1:1, which helps a lot

my car runs 11psi dead stock, no problems, im hoping to shortly swap turbos to one with less miles on it, intercool it and run 18psi, anything above 14psi in these cars need added fuel, and it has been known for guys to run 30psi on the stock cast pistons
 

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Discussion Starter #8
Tbird232ci said:
what size exhaust is he running? what kind of boost controller is in the car?
3" single exhaust, greddy profec B-2
 

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Discussion Starter #10
Tbird232ci said:
think about possibly running 3" duals, the less backpressure the better in a turbo car
I wish but not with a stock K-member. I have something much better in the works for my car but it requires a tube K and F C/Os.
 

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drool :cry:
 

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justin00stang said:
I wish but not with a stock K-member. I have something much better in the works for my car but it requires a tube K and F C/Os.
i didnt factor that one in there, is there a possibility of running a short section of mandrel 2.5 to 3" later on? that y-pipe, in any form would restrict the spool up a bit
 

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Tbird232ci said:
well, the 2.2's also have a compression ratio of 8.1:1, which helps a lot
It would, if I had a 2.2 in it. It had a 2.5L in it and the compression ratio was a bit higher, like 8.9:1.

Steve
 

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? The stroke is longer too. Same block, same bore, longer stroke. Longer stroke raises the compression ratio. Yeah you can deal with that by lowering the piston, but there is a limit to how low the piston can go before you have piston to crank counterweight issues. The 2.5L turbo was built to provide more grunt down low for the heavy minivans. it does that nicely, but it's not the high rpm screamer the 2.2 is. Lower the compression ratio too much and you lose the lower end grunt the 2.5 was used to provide, so it's kinda a wash. For the masses the slightly higher compression tratio 2.5 turbo provides a good balance between off the line (no boost) grunt and top end (got boost) power.

It's only when knuckleheads like me start turning up the boost that you got to be careful how far you go. And you got to do things the factory never considered proper for a turnkey setup for the masses. It was fun while it lasted and it was my brainfart that killed it, not any inherent lack in the stock engine. Never forget to hook up the wastegate control :rolleyes:

Steve
 

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lol did you say its a Twin turbo kit using 2 T-25 turbos?
 
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