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zukirider21
Well-Known Member
Alright, I gotta do a headgasket and and I'm wondering if I should clean up the intake and heads while im at it (using a little kit like the one from Standard Abrasives). Some people tell me that it's pretty rough in there. However, I know that the 2.9 is an impressive little motor from the factory (basically equivalent to half a 351 Lightning motor with peak power at a lower rpm) and is pretty finley-tuned as is. I also know that the 2.9 gets a little more air than it actually needs, and pulls best a little off of WOT. Now, would porting make that condition worse, or would it improve flow so much that I could possibly run a *LITTLE* bigger injectors?
Thanks
Thanks
. No such thing as too much airflow, only such thing as low port velocities our improper camming. The 2.9's only real weaknesses in it's flowing abilities are in the upper to lower intake port matching (upper ports are way smaller then the lower ones), and the exhaust ports are slightly too big (headers can kinda make up for poor velocity here). Port matching the upper and lower intakes is your biggest gain for the smallest amount of effort. Read through my tips for more information on it. Also keep in mind that head gasket problem you think you have is more likely a cracked head on these engines, not saying it's not possible, but have a machine shop check it out before bolting it back together. Larger injectors would only be needed well beyond these stages, as far as I know nobody on here currently has a 2.9 at that point (let me know if there is though, I probably have some tricks for them if they do). When you start pushing one close to 200hp flywheel then larger injectors and increasing fuel pressure become a factor. If you modify one of these correctly you can actually increase your fuel mileage on them, the more efficient of an air pump you make it at it's normal operating rpm range the more gas mileage you will get. I used to get close to 24mpg out of my 87 on the highway (4x4, automatic 30" tires and 4.56's). Granted the cost and time involved (numerouse intake and exhaust combinations) of this efficiency far outweighed the benefit, it was still fun too see how far I could push one. I'm not advocating anybody try a build like I did again, very expensive for the power gained (well the nitrous power was pretty cheap
). I did love the 2.9 for one major reason, It always seemed to run it's butt off for as small as it was, so it was a fun engine. If I could have my old 87's 2.9 back the way it was when I sold it, I'd be very tempted to put it in place of my 01's 4.0L SOHC motor, it simply had more useable power. Not that the SOHC motor doesn't have a ton more potential becouse it does. Just highly modified 2.9 vs stock 4.0L SOHC, my 2.9 was a better street engine. Now If I could get some more bottom end torque out of this SOHC I may change my mind a little bit, not too impressed with its low end so far (it's got 4.10's so that shouldn't be the problem). 
