BoostGuy951

Judging by the look of the intake port, I think there is some room for improvement. I think some metal could be removed from the port floor, and around the guide boss. Also radiusing the port just around the seat looks like it would improve flow. I am not looking for anything drastic, but I am having a 3 angle valve job performed, and the valves backcut, so I figured this might make a nice little project.

Has anyone tried this?

Russ Murphy

Not on my 951, but I did on my five cylinder Audi turbo head. Intake and exhaust port matching and some seat of the pant head porting and polishing. No real data to confirm whether I helped or hurt the cause, but the car ('86 4000 CS Quattro) ran like a scared rabbit at DE's where I was gobbling up stock 951's. You just need to think it through a little.

Russ Murphy

Oh yeah, I almost forgot. Those 4 amp Bosch die grinders are the most powerful tool that doesn't come in a fixture. Be damn careful.

BoostGuy951

I have got the little 30 dollar dremel extension thing, it works really well in tight spaces, its like holding a pen. I was also thinking about cutting my intake maifold runners into a few pieces, and then porting them and welding them back together.

AKS986

Russ Murphy- I am very intrested to hear about this 4000 quattro, did you do a swap or somthing? for some reason i was thinking they were slow as hell NA 4cyls or somthing. It would be great if you could give me a link to info on this car. Any mid 80s audi other then a s4 that could keep up with 951s in DE deff has my intrest. thanx.

shea

Russ Murphy

Boostguy,
I think you'll need a little more juice. Typically a die grinder with various spade-shaped carbide cutting bits are the tool implemented.

Shea,
It was a 4000CS Quattro (2.2L ,10v, 5cylinder) and while Audi made 4000 Turbo Quattros and even better yet the Sport Quattro (sort of a 4000 with the chassis shortened and only two doors, built from the ground up as a race/rally car) I turned my 4000 into a turbo by swapping the motor with the Audi 5000 turbo motor. Oh boy, is
CIS a lot of fun. I ran 12-13 psi instead of the stock 7-8 psi (which was good for 170 hp stock).

OZ951

Here is a link to a guide on DIY porting. porting guide

Phil Harrison

"I was also thinking about cutting my intake maifold runners into a few pieces, and then porting them and welding them back together."

Huh! They will never line up properly again & be worse than what you started with.

There is a process that uses an abrasive liquid - can't remember the name though.... Something hone perhaps?

turbo944

Called Extrude Hone I believe if I remember right. Although it it supposed to be get better numbers, I'm not sure on the matching of airflow from runner to runner with them done that way. Might make them more uneven or may help to even them out, depends on how good the place is doing the work and how meticulous they are I guess..... Best thing to do would be to check 'em out.

toddk911

no, but I hacve thought about using dremmel to shave the throttle body a bit.

Not sure about the intake except for polishing it yourself. If you are going to do the amount of work you are talking about, you should just build a custom intake. Long runners, big plenum!!

TonyG

Phil Harrison

>>>Huh! They will never line up properly again & be worse than what you started with. <<<

This is incorrect info. In fact, the only way to properly port the 951 intake is to cut the runners in 1/2, then cut out the back of the plunum.

You port, then you weld backup. And I can guarantee you not only will the parts fit back together properly, but you can see big improvements when combined with a properly ported head.

The extrude hone process is for the most part, junk. It's ok on some things, but it's a "poor mans" port job.

I can elaborate on the various reasons why, but suffice to say, that you will be better off cutting the intake apart, porting it, and welding it backup.

Been there... done that.

Here's pic of a properly ported intake....

Olli Snellman

Extrude hone process was "invented" in the '50's for aviation purposes.

TonyG

Olli Snellman

>>>Extrude hone process was "invented" in the '50's for aviation purposes.<<<

That may be... but it's no substitute for a real porting process.

Olli Snellman

Tony,
i totally agree with you. Extrude honing is no substitute for a porting process.

When i was a young student back in the late 70's i used to work during summertimes for Finnair. There i first time saw Extrude honing in live!
Of course i made friends with this guy who was responsible for that Extrude honing system.
Back then i read a lot Hot Rod magazine and they had just introduced Extrude honing. I was just building a turbo charged Chevy 327 engine for my friends '62 Nova 2 dht. Ofcourse i had cylinder head's intake & exhaust Extrude Honed ! It only cost me a bottle of Finlandia Vodka !! Don't know did this Extrude hone gave any benfits but we tried to to every possible thing we could imagine! That was in 1977 ! Time surely fly !

Phil Harrison

Tony, the original poster said "cut into a few pieces" that is not cutting in half, I stand by my comments.