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L35 4.3 Litre V6 |
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| The stock engine was a 4.3 litre L35 V6 rated at 180 hp in stock form. Not really a speed demon but not shabby eithor. My first modifications were the addition of dual electric fan's and an external engine oil cooler. It was about 110 degrees in Arizona daily in the summer and I felt that engine durability and power could be harnessed through these two mods. |
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| I removed the stock clutch fan and installed a set of LT1 cooling fans off an LT1 fbody. These worked out super well. |
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| I then ported the MAF sensor and found out that it actually took power from me on three separate occasions. I also obtained a GMS sensor and come to find out I was in the same boat. I found that the ported MAF actually made the motor lean out so much that the truck virtually got no fuel after 3300 rpm, not a good thing. I have a stock MAF sensor, stock airbox with a 3" hole cut into it, and have installed a custom made throttle body plate to replace the one with the restrictor on it. You can remove the restrictor off the stock one, but I have heard people say that the motor tends to race when they remove it even after the rivet holes are plugged which leads me to believe a air leak someplace. I don't even have the idle control hole drilled into the plate. I just went ahead and let the computer completely control the idle. |
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| My next mod was installing ceramic coated JBA headers. These little babies were a terrific kick in the pants improvement, including kicking a huge hole in your wallet, and leaving you scratching your head in the middle of installation wondering if all the work was going to be worth the gain you see? Well, it was worth it for sure. All these mods have increased my MPG and I feel have had no adverse effects on engine longevity. I hope you can see the headers in these pictures, they are really down in there and are hard to see. The one picture I took of the driver's side was when I was almost done putting them in. I had to take the inner fender loose to get to it. |
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Well enough of the mods and such lets get to the nitty gritty, the dyno sheets. |
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| This dyno was done with the following mods, JBA headers custom 2.5" catback, custom airbox, Efans installed, and Hypertech power tuning installed. My best ET was 15.9 @ 86 with these mods |
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Dyno is with the above mods and a GMS MAF sensor |
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Dyno is with the above mods and a ported stock MAF |
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Dyno is with a stock unported MAF in place |
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This dyno was done after on a few more modifcations to the truck but surprisingly alot of power was gained. Nothing was done internally to the motor. March power pulleys were installed, a full 3" custom exhaust, Poweraid TB spacer, and I also swapped out the stock parasitic 5 speed for a T56 off a LT1 fbody. The best ET made with these mods was a 14.9 @ 93. Just the 20 rwhp gained here made a world of difference. If you look the powerband is much much better throughout. A 3" exhaust is a must if you want to go fast with a 4.3 just by looking at the graphs above 4k. |
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GMS MAF sensor installed with above mods |
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Stock MAF sensor installed with above mods |
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