ju-on

Thanks for the link! It'd be nice if they sold a 2.5" stack though. I think that I need to have a 2.25" tube where it meets the head flange. But I want it to be a little larger coming out of the IM so I can have it taper down to 2.25" gradually all the way to the head flange.

I did find these stacks for pretty cheap, but I'll have to contact them because they don't mention the material it's made of, or the length.

http://216.120.227.145/~racings//prod_velocitystack.php

they are sold at Auto Barn for $23 which is the best price I've found yet.

http://www.archcartpro.com/users/aut...ELOCITY+STACKS

EDIT: Just found them here for even cheaper. http://turbofriendly.com/velocity.html

90dx

What size is the stock runner on a DSM intake mani?You going to weld to the stock flange just lop the runners off or buy make a new flange?Mike Weir can probably cut you a flange he is the man for that Is there a benefit to coming out of the intake mani large and tapering down vs just one size the whole way i dont know just asking?I think you want the total volume of plenum and runners to be 2-3 times the displecement but that is just a guess.

trustnoone7935

Too much reading,now my head hurts

Racintweek

just throwing some parts to gether to make an intake mani isnt a great idea. sure longer runners are better for down low, and big runners are for top end but it is more than just a general statement. there are a lot of things to consider,like, how big can you make the runners w/out sacrificing too much velocity??


there is more to manifolds than just runners and a plenum.

TorganFM

What you should do is look at a stock piece and analyze it while thinking about the objectives of the engine. Like if you have a high revving motor like a B16B you look at the IM design and compare it to a B20 IM. This is just an example, but you get the idea. From there I would go about modifying a stock IM to preserve an OEM look while getting the performance edge a performance IM would give.

unsivil_audio

IMO, your IM isn't the problem with power dropping off. What size turbo do you have? (FYI, big 16g, isn't "big.") Also, what cams are you running? Tubular or are your still on the crappy log manifold?

G2turbo_terror

http://www.mne.psu.edu/me415/fall05/SAE/intake.html

http://www.dune-buggy.com/turbo/intake.htm

I believe I have some .pdf articles too, if i do I'll pass them on to ya. IF you don't have/cant find some more math formulas I should have them.

Is choping off the stock plenum and welding a larger one on an option? You could add a larger TB of you choice, the runners could be shortened and you know the injectors are at somewhat of a "good" angle.

Guy-Fast

There are alot of routes to go with manifold work. Plenum volume and velocity are issues that need to be addressed. Really ported properly factory units atleast in the Honda world own most of the stuff out there. My dual throttle body manifold for my b20 is almost done. Naturally asspirateddd junk

seerex

This might help https://www.homemadeturbo.com/forum/...?topic=85979.0

ju-on

Hence the reason I started this. I don't want to just slap together parts. I want to build it myself, yet get some input on some "rights and wrongs" before I do it so that it ends up being worth my time.

In the DSM world, the stock IM is decent until you get into the higher RPM's. Some people have them extrude honed, but for the money that it costs to get it done, an aftermarket SMIM seems the way to go. The runners are just too long, and the plenum too small. Otherwise I'd be all about keeping the stocker.

Right now I'm on a 50 trim setup with the stock manifold at around 26psi. Cams are HKS 272's. But this winter the setup is changing over to an SLS tubular manifold, with an S362 hanging off it. I'm hoping to be flowing right around 60lbs/min with the new turbo, and the stock IM is going to be somewhere that is definately going to need some attention.


Thanks for all the links though, I will be digging through them all!