intake manifold - Toyota Nation Forum : Toyota Car and Truck Forums

high c · 06-28-2003, 11:54 AM

I want to re-build the intake manifold on my 3sfe.Dose anyone know why Toyota made the runners so long going into the head? and if I put a bigger plenum on will the help any?

rezzle · 06-28-2003, 12:42 PM

Quote taken from ...

http://sdsefi.com/techinta.htm

"Intake Runners

Runners are made from .050 to .065 tubing. Runner lengths can be adjusted within the space constraints to help boost torque within the desired range. Short runners are good for high rpm torque as in a racing situation. Long runners are more applicable for street use at lower rpms. For most street engines, try to keep the length from the end of the runner to the valve at least 9 inches long and preferably longer. Available space usually limits this dimension when using straight runners so curved runners using 90 degree mandrel bent tubing can sometimes be used to increase the runner length. As applied to engines with oval or square ports, you will have to form the tubing into the port shape which is considerably more complicated. Tubing should be cut off at precise lengths with a tubing cutter and carefully deburred. For maximum airflow, tapered runners with velocity stacks inside the plenum can be made if you are capable of this type of work. This is very time consuming but this design shows a 20-25% increase in flow over straight tubing runners."

Hotwheelharmer · 06-28-2003, 12:54 PM

Longer runners on an intake manifold help you produce more torque. The short manifold is for hosepower and seen more on turbo engines along with a bigger plenium. If you stay with normally aspirated I would suggest just sending your intake manifold out to extrude hone and let them do there work on it. With normally aspirated your power is produced by the engine itself not by another source forcing air in so you don't need that extra size for more air it will jsut be over kill. if you want to know more about extrude honing go to there site www.extrudehone.com It is a very cool process. My buddy has a 3sgte intake manifold that he got done by Hux racing and then he sent it to extrude hone and we compared it to a stock manifold and it makes a great different.

high c · 06-28-2003, 04:17 PM

thanks for the info. I will probly end up porting it out to mach the gasket and just cleaning it up

Hotwheelharmer · 06-28-2003, 05:03 PM

Are you talking about cutting the manifold and porting it all out and welding it back together or are you just going to port the outlet of the ports? If you are just porting the outlet you are probably not going to notice anything. On my intake manifold I cut it up and welded it back after porting it. This method works ok but you are not going to get it as evenly as if you get the manifold extrude honed. That process makes all the runners equal the whole time.

high c · 06-28-2003, 08:57 PM

so your saying get the manafold manifold extrude honed and that will make a big diffrence or chop it up and do it my self. Or I could just make a custom one out of 2" pipe

and have a 4" plunom

Hotwheelharmer · 06-28-2003, 09:08 PM

If you are staying with normally aspirated your best bet would be to get it extrude honed. You can cut it up and port it and that will be a good gain but you run into the chance of having the runners unequal. I wouldn't make your own manifold if you are going to stay normally aspirated. If you plan on putting forced induction on there then make your own manifold.

high c · 06-28-2003, 09:15 PM

this brings up a good Q to stay N/A or not. what will hapen if they are not all =?

Hotwheelharmer · 06-28-2003, 09:21 PM

If they are not equal you can run into problems of imporper air/fuel mixture in cylinders and causing some cylinders to be rich and other to be lean and it will run terrible. Plus with the lean cylinders you run into chances of detonation and other damage to your internals. Unequalness will also cause hot spots in your internals as well.

high c · 06-29-2003, 07:28 AM

how did that intake man. you hade on your web site work out, the one you were going to test?

Hotwheelharmer · 06-29-2003, 09:10 AM

Are you talking about the one that is blue? That is the one I have on my car now. I don't know excatly how much power I got out of it but it was evenly done. When I put the manifold on I also put on my head that I built and oil cooler so I can't really say excatly the power gains but I am sure there was a little bit of gains. If I got a bigger throttle body and bored out the inlet on the intake manifold to match it I would notice real gains from the manifold.

jm_2thow · 06-29-2003, 10:34 AM

you can do one evenly by yourself, just seal off the side that goes into the head and then fill the runner up with water untill u see it get flush with the pleneum, dump the water out, measure it, repeat for the other runners and make sure they are all the same

high c · 06-29-2003, 08:58 PM

ya the blue one. ya I'll try the water thing too. do you think hooking up twin TB it would help any more