Better throttle response
#1
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Location: Detroit
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Year: 1997
Model: Cherokee (XJ)
Engine: 4.0L
Better throttle response
Can someone tell me what size throttle body i should use..i want to install some 12 hole injectors and i am going with a 62mm throttle body...but my buddies said i can go larger..how large can i go with my tb...and does anyone have a part number for a correct set of 12 hole injectors..there for a 97 xj with a 4.0L eng..
#2
CF Veteran
A 62mm is fine. 12 holes are not going to add any power that wasnt already there with good working stock injectors. You could save your money on those 2 items and put it toward an ECU tune that will probably net you more gains.
#3
CF Veteran
Many people have better throttle response after switching to 4 or 12 hole injectors. I have 12 hole injectors, APN header, 62 MM throttle body, and a 2.5" exhaust with no cat and my throttle is very sensitive.
#4
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Location: Detroit
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Year: 1997
Model: Cherokee (XJ)
Engine: 4.0L
#5
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Disagree with the injectors, I added 4 holes and the response off the line was immediate and noticeable.
#7
CF Veteran
The price I got from the mods above comes out to $600-700. I would bet that more power and responsiveness can be had with a 89 octane tune for less money. Those gains would be backed with objective data from the tuner.
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#8
CF Veteran
Who makes tunes for our computers, and can they tune it so it will make more power but still run regular 87? There is no way I am paying for premium fuel.
#9
CF Veteran
JTECs can be reprogrammed. Syked ecu, Flyin Ryan and maybe Chris tuned if he is still at it. 89 is mid grade but allows more advanced timing. I run premium 93 on my set up and for what I get out of it it's worth it to me.
#10
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Join Date: Oct 2013
Location: Greenville, SC
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Year: 1999
Model: Cherokee(XJ)
Engine: 4.0
Everything I had seen pretty much said that 4.0s are tapped out from the factory and a tune doesn't really change much on them. I've never very seriously looked into a tune though.
#11
CF Veteran
Contact one of them and see what they can do for you. Personally I would go to Ryan first because he works directly on the JTEC ECU and has a very good reputation.