What is needed when you change a pulley?

[03 TWIN]

A friend of mine has an 08 gt500. He changed the upper pulley, put a jlt cai, and a handheld tuner. He says it bogs down around 3-4.500 rpm when accelerating hard. Car has tr6 plugs gapped at 30. He hasn't put a tensioner on it yet and may be getting belt slip. What else could be the problem?

 

[evolve]

needs a good tune maybe?

 

[09Troublemaker]

what tune is he running?

has he checked all his work. more then likely its in his tune

 

[03 TWIN]

I was thinking plugs or tune. I've never liked the handheld tuners. Is 30 good enough for the plugs?

 

[STG]

He needs to fork over A few hundred dollars for a custom dyno tune. Get the car on a dyno.

Shelby GT500 Mustang - $45,000

EL Cheapo canned tune - $295

Bogging between 3,000 and 4,500 RPM - Priceless

 

[03 TWIN]

He needs to fork over A few hundred dollars for a custom dyno tune. Get the car on a dyno.

Shelby GT500 Mustang - $45,000

EL Cheapo canned tune - $295

Bogging between 3,000 and 4,500 RPM - Priceless

I agree on the dyno tune. :beer:

 

[Blaine]

I agree on the dyno tune. :beer:

+1. I may use a tune over the internet for a CaI only from a well known tuner, but once you start tossing in smaller pulleys and other mods I'd recommend a custom tune.

A. Belt slip? Possible depending on how small of a pulley hes using.
B. Bad Tune?
C. Plugs?

If it is A. his car will be fine, but if your running the crap out of it with B or C being the problem... you may be causing alot of harm to the engine. Good way to burn a piston.

Also, if your running a smaller pulley you better tell your friend to buy himself an upgraded Heat Exchanger.

 

[ZXMustang]

Get a tune, and gap the plugs to .35

 

[Bravo gt 500]

Does he have an idler for the smaller pulley?

 

[me32]

where did the tune come from?

 

[03 TWIN]

Does he have an idler for the smaller pulley?

No Idler

where did the tune come from?

Sct x2 tuner

 

[FastOldGuy52]

He needs the idler.

 

[chuckstang]

He needs a tune from Lethal or Evo...

Those Canned tunes are perfect

 

[sharke]

It could be too hot and pulling timing. He should datalog to find out for sure. Maybe AFCO or RR is the solution?

 

[me32]

No Idler



Sct x2 tuner

if its just an SCT X2 with no proper tune for the JLT then thats the problem right there. contact a tuner ASAP, you cant break the engine realfast if you dont.

 

[09Troublemaker]

I'm fooling around with different pulley sizes............
she will be on the dyno getting a new tune this weekend
best $400 I'll spend...piece of mind = priceless