87 XR4TI Turbo HP is down...why?

[1996CobraConv]

I have an 92 Mustang LX that was an original 4 cylinder/ 5 speed car that has had the XR4TI engine swapped before we bought it. The car runs good as far as idle and no hesitations, misses, stumbles, etc. It is running 10lbs of boost (non-intercooled). It appears to have been a clean swap and the guy tells me the wiring harness and all was also swapped, has the Walbro 190lph fuel pump and regulator.

Now for the problem...Just got back from the dragstrip which confirmed what my rearend had been telling me as well. The horsepower just isn't there, a whopping 76mph in the quarter. I am new to the turbo 2.3 (longtime 8 cyl. guy), but looking at research of what the xr4ti did stock and I am a good 6-7 mph off of what it ran in the, probably heavier xr4ti!!!

It seems that it starts to pull half decent to about 3500 rpm and then just levels off. The boost never lowers and in fact toward redline is close to 11psi. As I said b4 it doens't sound bad or anything it just doesn't pull like I know it should. What could be causing this? I would appreciate any help anyone can give me. Thanks, Dan

 

[Turbo_Raccoon]

acctually 76 mph is pretty good cause my 79 with a 2.3 turbo runs that in the quarter with 8 PSI and you could turn the boost to about 15 with no problems. and if the motor has no goodies on it then you ran well.

 

[Stinger]

The main problem is the boost level. Turn it up to 15 and watch it come to life. You should pick up about 8mph. Also, check your timing and make sure it's at 12-13º BTDC at idle with the spout unplugged. Then, make sure you have premium in it and make some pulls and listen for pinging (detonation). It sounds like someone rattling rocks in a tin can. If you don't here any, it's safe to run.

Also, two huge mods are a K&N cone filter and a 3" downpipe or 3" exhaust. These two items will get you about 25-30hp by themselves.

If you have no way to adjust boost, go to www.boostvalve.com and buy a valve for 45 bux.

With a boost valve, 15psi, K&N, and 3" downpipe, you should be trapping in the low 90's.

Oh, and the Merkurs are only about 2800-2900 lbs also.

I'll sell you a 3" downpipe for 95 shipped.

 

[tb9050lx]

I have an 92 Mustang LX that was an original 4 cylinder/ 5 speed car that has had the XR4TI engine swapped before we bought it. The car runs good as far as idle and no hesitations, misses, stumbles, etc. It is running 10lbs of boost (non-intercooled). It appears to have been a clean swap and the guy tells me the wiring harness and all was also swapped, has the Walbro 190lph fuel pump and regulator.

Now for the problem...Just got back from the dragstrip which confirmed what my rearend had been telling me as well. The horsepower just isn't there, a whopping 76mph in the quarter. I am new to the turbo 2.3 (longtime 8 cyl. guy), but looking at research of what the xr4ti did stock and I am a good 6-7 mph off of what it ran in the, probably heavier xr4ti!!!

It seems that it starts to pull half decent to about 3500 rpm and then just levels off. The boost never lowers and in fact toward redline is close to 11psi. As I said b4 it doens't sound bad or anything it just doesn't pull like I know it should. What could be causing this? I would appreciate any help anyone can give me. Thanks, Dan

iff the engine came out of an automatic merk the horesepower will be down to about 140 the c3 in these cars sucked and thay had less boost and a diffrent cam to make less power so the tranny would hold up.i had an 88 auto with 90,000 and an 86 with 140.000 on it when the 86 with the stick blew up we swapped engines and it was never right felt slower and the boost would only peak 11psi .years later i found out they had diffrent cams and boost settings so you might wanna look into that

 

[Mr. Merk]

i knew a guy running 12's on a stock C3

anyway, yes the boost is prob where your power loss is at, turn it up, they ran closer to 15psi from the factory

get you some nice 3" exhaust and a K&N and most importantly a boost controller (but be VERY careful turning it, been there, 25psi once and the gasket blew)