legacycentral bbs

i'm just wondering if the hks wrx down pipe is a direct bolt on for 91 turbo sedan . sorry if it's a newbie question but i just got the car 3 days ago.

http://bbs.legacycentral.org/viewtopic.php?t=18633
http://bbs.legacycentral.org/viewtopic.php?t=15784
http://bbs.legacycentral.org/viewtopic.php?t=14637

That's a piece of shit downpipe too. You're better off waiting until you can afford a better one.

-Brian

Since I like straight answers instead of "search noob" type responses, I'll give you a straight answer.

Any of the WRX downpipes will work for us, but you need to do a custom piece for the midpipe (or extend it).

I have a Stomung twin dump and am very happy with it.

But if he had spent 5 minutes seaching, he would have got a straight answer...

And from what I saw, Vikash didn't say anything about "search noob", but provided him with links that would answer his question so he wouldn't have to search.

and you dont have to get an extended midpipe unless your doin a full setup and you dont need a dp extension unless you get a shorty like the stroumng. and you need to extend the o2 sensor or get it rebunged

mikec wrote:But if he had spent 5 minutes seaching, he would have got a straight answer...

And from what I saw, Vikash didn't say anything about "search noob", but provided him with links that would answer his question so he wouldn't have to search.

Wasn't directed at Vikash. Just the whole search noob attitude. It's often quicker to answer the question than flame someone.

why is it so bad?

is it the plate?

i dont understand downpipes very well. it seems that all 3 types have problems.

is the HKS better than stock? if so i would imagine it would be worth it if the price was right.

what about a custom DP?

Flat plate downpipes are low-tech, and generally junk. They just cause a lot of unnecessary turbulence.

Bellmouths's have a wirlpool of air in the center of the bellmouth that actually will suck the wastegate flapper open, and this will create a bit of boost spike and creep.

Divorced is great if you can truely seperate the wastegate from the main. CES is the best company I've seen that can do this. No one else comes close. The cost is the only limiting factor. They are the absolute best designs if it is done right. I know CES is done right.

A custom DP is going to most likely use a bellmouth pipe, and for the above reasons I'd never get one.

The HKS is BARELY better than stock. There is a LOT of room for improvement.... Unless you have an externally gated wastegate, then the HKS joint is good because it's simple.

the bellmouth only creates that whirlpool that sucks the wastegate open if the pipe off the bell is centered in such a way that the air meets directly in the middle of the pipe. but because the wastegate is smaller than the outlet and the pipe off the bell usualy is stagered the wastegate being sucked open is a nonissue. plus this is the only palce ive ever heard of this problem. ive never heard wrx guys or legacy people complain about creep problems because of a bell mouth

I think it might have to do with the tiny turbo we have, but I have heard some of this at the RSLib forums. But they seem to think the divorced WG will cause more boost spike. I have a Custom bellmouth that I made, Zero creep or spike.

I also think that the price hks DP's are going for it has to be worth it. Most Legacy SS owners are not going to mod enough to need the best, most expensive DP on the market.

The HKS is BARELY better than stock. There is a LOT of room for improvement.... Unless you have an externally gated wastegate, then the HKS joint is good because it's simple.

Complete bull. Anything that eliminates the horrible OEM downpipe design is lightyears ahead of the stock exhaust. Ignoring the mouth design, since that will only find you maybe 10whp on a dyno (and tons of $$$)... the HKS is excellent because it eliminates the almost 90 degree bend the stock downpipe makes with a cat on top of that. And it provides a very smooth exit path from the turbo which will love you for it. You will find that the car will hold full boost all the way to redline with a 3" downpipe and system. On a real cold day, you might get some problems with boost creep. But if you reset the ECU so it can get used to the coldness, it will handle it a lot better. I speak from experience. My system has an OEM style dp flange with 3"exhaust and does fine.

There's nothing wrong with the HKS downpipe. Unless you're making HUGE power, you can't beat it for the price. Anything is better than 2" pipe with a 90 degree bend into a cat. You don't have to spend 47893476237823$ on a downpipe to get good results.

William - The HKS downpipe is a Flat plate downpipe, the same as stock. The bellmouth pipe isn't an HKS pipe.

Jason - A friend of mine has a Bellmouth downpipe. He has problems. It's more likely due to the wastegate flapper being partially open (under partial throttle acceleration), there is a void of air and a resulting vacuum that will suck the wastegate open under partial throttle acceleration.

That probably DOES have something to do with the tiny turbo and weak wastegate like -K- said.

You guys can run whatever downpipes you want. I'm just telling you about my experiences with them.

I'll stick with my CES pipe

to bring this thread back to life, I am thinking about buying am HKS DP, but the flat plate kinda freaks me out. I would think (keep in mind I am a noob) that the flat plate would create iffy turbulence. On the other hand though, I don't think enough air comes out of our little turbos or wastegates for this to harm it. I have a stock 94 SS and I will be running a QTP electric cutout straight off my DP if I go HKS or stock, but there is an HKS DP for sale in my local on nasioc right now for about $100 and I am wondering if I should buy it and get it installed before my cutout. Has anyone else had an practical experience with the HKS flat plate DP?