CantonXJ
NAXJA Forum User
- Location
- Canton, CT
Just wanted to pass along my experience with the installation of a 62mm throttle body this past weekend for those who may be contemplating this mod. First off, my XJ is my daily driver and is basically stock except for a K&N FIPK. I saw the installation of a bored-out TB as an easy way to gain a little power and perhaps even an increase in gas mileage. My next upgrade will be the installation of a freer-flowing cat-back exhaust system. Probably a Dynomax Super Turbo system from Summit 'cause I'm a cheap-o. 
I did a bit of research in trying to find the "right" place to buy my TB. I checked the usual places, but finally settled on one from Jeff Leigh at Leigh Performance Machine (http://www.strokedjeep.com/). I purchase it through his eBay store because of his free shipping and low core charge ($60). Jeff's eBay seller ID is jeffl931 and he always answered my questions quickly and offered valuable tips on installation. I received my TB within just a few days and I must say I was amazed by the quality of Jeff's craftsmanship and attention to detail. The TB was finished in a beautiful, wet-black powder coat finish and the throttle plate was perfectly machined for a precise fit. I couldn't wait to get this puppy bolted onto my XJ.
First, I disconnected the positive side of the battery. Getting the old unit off entailed merely unplugging the electrical connectors from the three sensors on the TB and disconnecting the throttle and transmission cables (I have an auto trans.). Then, using a 10mm socket, I backed out the 4 bolts securing the TB to the intake manifold. So far, no sweat whatsoever. Next came moving the 3 sensors from the old TB to the new one. This requires the use of a T-20 torx driver. I had a bit of difficulty loosening a few of these screws for fear of shearing them off. However, I found that if I tapped the center of the screws with the torx driver and a hammer, they came out with no problems. A drop of Loctite on each screw had the sensors mounted on the new TB within minutes. Even though Jeff had sent me a new gasket to mount the TB, it appeared that old one was still in good enough shape to have re-used. I elected to use the new one just to be safe. I carefully lined-up the gasket and throttle body on the intake and installed the 4 mounting bolts almost finger tight. While the TB was still just slightly loose on the intake, I made sure that the throttle plate was able to fully open without scraping either the gasket or the intake itself. Jeff had pointed out that many of the "whistling" problems associated with bored-out TBs was due to misalignment as well as poorly machined units. When I was satisfied with the alignment, I tightened the 4 bolts, but not overly so. My XJ's intake is made of aluminum, so overtightening could do some major damage to it. A few minutes later I had all the electrical connections back in place along with the throttle and transmission cables. It was time to start her up!
I had read elsewhere to expect a high idle and some rough running until the engine's computer has had time to re-adjust itself to the increased air flow of the new TB. However, much to my surprise and delight, my XJ started right up and immediately settled into a nice, smooth idle of about 700rpm. I, of course, hopped right in for a test drive. First thing I noticed was that throttle tip-in and response seems more immediate and there are absolutely no flat spots from idle through full throttle. And there is absolutely no whistle at all! I am absolutely thrilled. I can't say, for sure, whether I "feel" any real
HP improvement, that'll take a little more time. I'm hoping that this, along with my K&N FIPK will squeak out another 0.5 mpg or so. Although, with the improved throttle response and throaty intake sound, I doubt I'll give it a chance to return any mileage improvements. ;-)
I just wanted to share how happy I am both with this modification and where I got it from. I hope it helps a few who have been contemplating this change to go ahead and take the plunge, you won't be disappointed.
Dave
I did a bit of research in trying to find the "right" place to buy my TB. I checked the usual places, but finally settled on one from Jeff Leigh at Leigh Performance Machine (http://www.strokedjeep.com/). I purchase it through his eBay store because of his free shipping and low core charge ($60). Jeff's eBay seller ID is jeffl931 and he always answered my questions quickly and offered valuable tips on installation. I received my TB within just a few days and I must say I was amazed by the quality of Jeff's craftsmanship and attention to detail. The TB was finished in a beautiful, wet-black powder coat finish and the throttle plate was perfectly machined for a precise fit. I couldn't wait to get this puppy bolted onto my XJ.
First, I disconnected the positive side of the battery. Getting the old unit off entailed merely unplugging the electrical connectors from the three sensors on the TB and disconnecting the throttle and transmission cables (I have an auto trans.). Then, using a 10mm socket, I backed out the 4 bolts securing the TB to the intake manifold. So far, no sweat whatsoever. Next came moving the 3 sensors from the old TB to the new one. This requires the use of a T-20 torx driver. I had a bit of difficulty loosening a few of these screws for fear of shearing them off. However, I found that if I tapped the center of the screws with the torx driver and a hammer, they came out with no problems. A drop of Loctite on each screw had the sensors mounted on the new TB within minutes. Even though Jeff had sent me a new gasket to mount the TB, it appeared that old one was still in good enough shape to have re-used. I elected to use the new one just to be safe. I carefully lined-up the gasket and throttle body on the intake and installed the 4 mounting bolts almost finger tight. While the TB was still just slightly loose on the intake, I made sure that the throttle plate was able to fully open without scraping either the gasket or the intake itself. Jeff had pointed out that many of the "whistling" problems associated with bored-out TBs was due to misalignment as well as poorly machined units. When I was satisfied with the alignment, I tightened the 4 bolts, but not overly so. My XJ's intake is made of aluminum, so overtightening could do some major damage to it. A few minutes later I had all the electrical connections back in place along with the throttle and transmission cables. It was time to start her up!
I had read elsewhere to expect a high idle and some rough running until the engine's computer has had time to re-adjust itself to the increased air flow of the new TB. However, much to my surprise and delight, my XJ started right up and immediately settled into a nice, smooth idle of about 700rpm. I, of course, hopped right in for a test drive. First thing I noticed was that throttle tip-in and response seems more immediate and there are absolutely no flat spots from idle through full throttle. And there is absolutely no whistle at all! I am absolutely thrilled. I can't say, for sure, whether I "feel" any real
HP improvement, that'll take a little more time. I'm hoping that this, along with my K&N FIPK will squeak out another 0.5 mpg or so. Although, with the improved throttle response and throaty intake sound, I doubt I'll give it a chance to return any mileage improvements. ;-)
I just wanted to share how happy I am both with this modification and where I got it from. I hope it helps a few who have been contemplating this change to go ahead and take the plunge, you won't be disappointed.
Dave
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