Intake modification questions....No, not a cone filter...
03-28-2005, 02:32 PM
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Intake modification questions....No, not a cone filter...
Ok. I'm receiving a intake header and throttle body, and was wondering if I can get any gain by polishing the inside of the header, and boring out the throttle body...
I know there is the fact that to have a noticable gain in horsepower, you should free up exhaust too...that's been done. I have a MSDS Header, and a 3 inch that goes to a 2.5 out the back...
Also, how much hp does painting the outside of the intake header red get me?
But in all seriousness, would it be worth the money to polish the intake and bore out the throttle body?
edit: cylinder head has not been polished, cams are stock...
I know there is the fact that to have a noticable gain in horsepower, you should free up exhaust too...that's been done. I have a MSDS Header, and a 3 inch that goes to a 2.5 out the back...
Also, how much hp does painting the outside of the intake header red get me?
But in all seriousness, would it be worth the money to polish the intake and bore out the throttle body?
edit: cylinder head has not been polished, cams are stock...
03-28-2005, 02:41 PM
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I would say there'd be 3-5 HP at the most, meaning no noticeable gain by butt-test even. Remember you are still runniing stock AFM Geoff. An MAF kit would be beneficial to the polished intake manifold and big bore throttle body. Keep in mind though if you are going to get your manifold polished, be sure that the whole inside is polished or else it's just not worth the price to polish the ports up to the center of the intake manifold. Reason why I'm saying this is because it's failry difficult to polish the middle part of the 944 intake manifold.
03-28-2005, 02:51 PM
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Just been thinking about the whole AFM/MAF kit... the ammount of air that can be allowed is restricted by the smallest part, the AFM... if I found a MAF or found a way to open the AFM, that'd be good.....Bah...the search continues, the pocketbook empties...
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03-28-2005, 04:07 PM
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what is the size of the afm? ford on the turbo cars used a smaller one and a larger afm on the svo and the 87-88 turbo coupe. the plug on my svo is the same as my 944. i think the inlet for the ford large afm is 3.5" and the outlet is 3".....BUT to change the afm in the fords, you have to change the computer that reads it, and change the injectors.........so do you think you can do this and just tune(i dont know how) the afm to give the computer the correct(same) voltages as the original smaller unit? check around, i have a reman. unit on my car....but im pretty sure ford was using a bosch part. look for large ones on nissan 300s, bmws and mercedes. i know the one on my friends' 300 was also a bosch unit.....and all had the same plug end.
03-28-2005, 06:24 PM
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Upgrading to lager runners and a TB that's about 30% bigger on the 16V 928's shows maybe a 1hp gain on the dyno. Some have been able to tweek more power with this setup playing with timing and fuel pressure, gains are still minimal.
03-28-2005, 06:34 PM
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Alrighty. Methinks then I'll use my new intake as something to play with visually instead of performance wise.... What color should I paint it? Cam tower is red...I'm considering polishing the outside....
03-28-2005, 08:38 PM
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Polishing the outside would look good. I ended up painting mine black which also turned out pretty good. Ill post pictures if you would like. (My cam tower is also red)
03-28-2005, 09:14 PM
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all the newest hottest tuner advice is saying to do nothing to polish or enlarge the intake tract... that it steals power across the band. Only thing I would do is match up the mating surfaces between pieces, and get rid of any huge irregularities that may exist.
03-28-2005, 09:58 PM
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There aren't any huge or really considerable problems with the intake tract. Most say to "gasket match" Porsche did this already. I worked with a guy at Porsche and drag raced on the side. He ported heads and did other machine work too. He said that stock was about the best "out of the box" he's seen. Not much room for improvement unless you get well beyond stock #s. Enlarging the intake system is kind of a waste if you are still running the AFM, it's the worst restiction in the system, larger would still have the barn door and not be much improvement for the work done. I think that alot more could be done with a nice exhaust, intake and a tuned cam for the setup. The stock cam has little to no overlap, meaning no scavaging. It's breathing about the best it ever will with the stock cam really. Just my thoughts.