Has anyone looked at the intake manifold->head and throttlebody port matching? Most cars are not smooth and are not matched well at all. I know we have talked about the TB size before and it seems like there is little room for improvement (although i think there is some room). but what about good matching and well rounded and smooth runs? I ask because I have the change to grab up a spare intake manifold that I can polish up without having downtime on my car, but its not free =) is it worth the investment? If so, I can do some for u guys too.

note: the guy that had the 14.2 sec NA ralliart had a bored TB and ported intake =)

 

How much of an investment are you talking about? and what else did the NA 14.2 car have?

 

gasket matching the IM will be good. Do not try to go beyond the edge of the gasket. It won't do you any good and may cause problems with leakage. Opening the plenum some will be good too (I usually do 2.5-3mm ).
Do not attempt to open the TB using hand tools. You need a lathe (or CNC) to properly open the throat of the TB and then you need to machine a butterfly to match. This can be pricey to have done, but shop around.

I don't know how open the 4G69 IM is, but the 4G94's was in need of some work. Gave power across the band with an increase on top and no noticable loss of torque.

 

lrh: under $200 for the parts, and I'll be able to sell mine when im done (or port & sell them).

eb: yea, going past the gasket is kinda pointless. i wana get as close as i can, but its my first shot so i dunno how its gonna turn out. all i have to work with is a dremel so i may need to break down and get a good variable speed drill =) if the tb outlet isnt smooth, i may try to touch that up, but i think it will be fine. didnt plan on trying to open it up any. i'll price some local shops tho.

i plan on hitting up a dyno tomorrow so ill be able to tell if it makes a diff =)

 

well, not exactly pointless if you're willing to do the work to the head that's necessary to take advantage of the extra air, and you need to modify or make a new gasket. But it's soooooo much extra work

I recommend an electric die grinder from Harbor freight, a bunch of sandpaper rolls, the proper size of mandrel for the rolls and WD40 as lubricant- Use liberally! I don't think the dremel's grinding attachments are up to the job.... but give it a shot if ya wanna

 

i didnt think the dremel would do it. talked to a friend with some better tools and will prob borrow that =) i figured the head would also need to be done. cant get a extra head yet, so that will have to wait until I have a day or 2 when i dont have to go anywhere =) either way, if it increases the air velocity at all, it should be a small improvement.... and i enjoy this crap, so why not

 

hey dudes , whats whith the 14.2 ralliart , i really want to know if that time is whitout (nos)because if not dammmmm

 

There's gasket matching on the head, and there's opeing up all the ports so they're ridiculous big.... that's what I was referencing.

Do you have the shop manual yet? I'd put my hands on one so you can get all of the timing mark locations, bolt torque specs and order and stuff like that. I'd also allot 4 fulls days for the first tear-down, port and rebuild. It's pretty demanding. I managed to do a tear-down, valve swap and rebuild in 12 hours by myself (the second time I did it), but the porting took a lot of time (I might be able to do it in 13 hours next time). And god forbid you run into a problem......

 

EB is correct. It's very time consuming. You need a a lot of patience. If you rush it in any way, you'll take off more material than needed. Of course, you can't really fix the boo-boo.

 

yea, thats why i wanted to pick up a spare and do the work do it, then swap out for the parts that are on the car presently. that way i can take my time and only focus on doing good work =) if i cant get a replacement header, then when it comes to that time, its easy to take off and i have some experience under my belt to help out with the process.

and yea, i go the shop manual /w all the specs. its kinda hard to navigate (html based) but i should survive =) thx for all the advice. any URLs for details on the actuall process? i have a pretty good idea, but wouldnt mind seeing how some others have approached it

 

BLK-majik,
keep us posted. This sounds like a worthwhile investment.
Engineerboy,
You say that you can get the TB bored out at local shops. You mean any machine shop or performance car shops? I'm interested in this.

 

might just use the extra to send away ahve the core done by someone else. some local machine shops could do it, or i could ship it back to PA to some ppl i know there. im def not gonna try to do the TB myself, but its enough to have a local shop turn around the cores for me =) would also need a new butterfly flap to fit the bigger bore

 

sounds like a stupid question, but why is it so time consuming???? is because when your making it bigger it all has to be equal??? i'm not a mechanic. i know a little but that is far as is goes. thanks

 

because there's no fast way to remove the material, and there's certainly no fast way to remove the material safely. Especially in the case of headwork, you need to be judicious in your metal removal - remove too much in the wrong place and you just killed your torque, or maybe you made it so the gaskets won't seal. So I do a little work with burs and then the rest with sanding cylinders. A little fast to get the process started, and thn a lot of slow. On top of that, there's no way to get a grinding tool into some of the spaces on the head, so you have to use little squares of sandpaper on your finger to round stuff off, or to smooth transitions.

There is one "easy" way to port- it's called acid porting. You block the bottom end of the port and pour in a strong acid and wait. BUT - it takes the same amount of metal from everywhere, so you can't control how it improves flow, and is potentially very dangerous.

 

for $200 ASP will bore any t-body. There the company that makes underdrive pulleys for race cars.

I would like to find out more about the 14.2 sec ralliart