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manifolds... tubular headers.. etc.

Thalomos

Proven Member
183
0
Aug 2, 2002
Jacksonville, Florida
I've noticed alot of faster cars on here and other DSM sites are running the stock manifolds (ported, 2G, etc) and i was wondering if getting an aftermarket set of tube headers was really worth it? Also those people with the aftermarket tube headers on their car (i havn't seen any) can post what they believe :)
 

turbolover2

Proven Member
387
1
Oct 5, 2002
Long Island, New_York
I don't think anyone makes tubular headers for the Mitsu type exhaust housing. But there are people going very, very fast on a stock-type manifold. So, unless you plan on being a record breaker, I wouldn't worry about it.
 

L2RTSiAWD

Honorary Moderator
Proven Member
11,533
22
Apr 8, 2002
Chandler, Arizona
Originally posted by BoostinAWD
There is another one to add :thumb:

Yes yes I have been slacking in my parts guide updating. I have a big update planned on friday though.
 

burnerkg

Probationary Member
8
0
Oct 16, 2002
Biloxi_MS
yeah, but i'm curious about the real question.....does anybody have the tubular headers and what is the performance increase
 

dsm156

Probationary Member
23
0
Sep 27, 2002
Salt_Lake_City_UT
Stainless steel has a lower thermal conduction constant then mild steel or cast iron...
I believe SS manifolds actually hold more heat in then a cast manifold, but I could be wrong. At the same time though, a tubular header does have more exposed surface area.

Air flow velocity also equals energy... Which manifold do you think would have a higher airflow velocity? Oh yeah, and kinetic energy of the air increases with the square of air velocity, where heat energy is linear to the heat transfer rate.

I believe a few individuals have tried them out and stated they picked up very large gains (40+ hp).

I am going to do one on my car in the future (hopefully near future at that).
 

rdrkt

Proven Member
1,544
2
Apr 20, 2002
Baltimore, Maryland
Originally posted by dsm156
I believe a few individuals have tried them out and stated they picked up very large gains (40+ hp).
I have seen people pick up about that much using a new intake manifold but I have NEVER seen anyone gain anywhere near that much HP from a manifold swap.
 

TSi92

Proven Member
471
1
Oct 18, 2002
Wahiawa, Hawaii
You need good velocity and with big tubular headers you lose lots of velocity, the result is lots of turbo lag. I say stick to the 2G manifold unless you going flat out racing.
 

dsm156

Probationary Member
23
0
Sep 27, 2002
Salt_Lake_City_UT
Most tubular exhaust runners are only about 1 5/8" outside diameter. That is roughly the same cross-sectional area as a stock 2G manifold. That doesn't seem too big to me...

Like I said, I saw claims of that magnitude. That doesn't mean those claims where substianted by a reputable person or in a scientific manner. However, I regularly hear of Honduh owners seeing those types of gains or larger when converting from manifolds of similar design to the stock 2G to equal-length tubular manifolds.

Something you have to take into consideration is boost pressure. If you are maxing out the airflow capacity of the turbo you are running, you will not pick up more power. But you will be able to turn down the boost pressure and make just as much power. This has benefits on pumpgas since you can run lower boost and more aggressive tuning with out detonation.

On a turbo that has reserve capacity at the boost level you are running, you will pick up substantial gains.

Just because tubular manifolds are not big in the DSM community doesn't mean that they don't work well. And just because somebody went 11.00 on the stock manifold doesn't mean that there are not gains to be had with going to a tubular manifold. This is like high compression on FI motors...just because the majority go fast on relatively low compression and high boost pressure doesn't mean high compression and low boost doesn't work...ah, never mind, different subject...

It just depends on where you want to get and how you want to get there. This is just my opinion though...
 

NDgsx

DSM Wiseman
1,163
3
Jun 10, 2002
Vancouver, Washington
Originally posted by dsm156
And just because somebody went 11.00 on the stock manifold doesn't mean that there are not gains to be had with going to a tubular manifold.

Try high 9s at over 140mph.

Do the gains offset the cost though? How well will the manifold hold up to continuous heat cycles on a daily driver?

Personally they only way I would consider a tubular manifold would be if I had a weekend only car or it was made out of inconel.
 

dsm156

Probationary Member
23
0
Sep 27, 2002
Salt_Lake_City_UT
True...I forget to mention my car is a weekend warrior...thus my slightly different outlook on the matter...

Inconel...yummy...are we building an F1 here or what?

Who went 140+ mph on the stock 2G manifold?

I will eventually move to the tubular exhaust manifold...but the setup I am planning on using is far from the typical DSM setup so...

There are a few SS manifolds available for about $600, which seems quite reasonable to me if they do pick up 20-30 HP. That is about as much as cams make and cost and people do those all the time. Matter of fact, I have ordered three sets of HK$ cams in the past week and a half for friends...
 

KenTSIII

Proven Member
495
1
May 29, 2002
Indianapolis_IN
"Who went 140+ mph on the stock 2G manifold?"

Curt Brown 9.87 @ 145.75. Without nitrous. FP red, Indy Race Core, Shep Racing motor & tranny, 272s, not sure about the rest.
 

NDgsx

DSM Wiseman
1,163
3
Jun 10, 2002
Vancouver, Washington
Originally posted by dsm156
Inconel...yummy...are we building an F1 here or what?

No, I just like overkill and pissing off my welder :thumb:

I would still do a sheetmetal intake manifold first. The stock runner length is tuned for 6,200 and you are pretty much limited to making peak power there, unless you shorten the runners.
It would be interesting to test a tubular exh man with the stock intake manifold, a sheetmetal intake manifold with a stock exh man, and then the sheetmetal intake manifold with the tubular exhaust manifold. If only I had tons of cash to burn on the dyno.........
 

dsm156

Probationary Member
23
0
Sep 27, 2002
Salt_Lake_City_UT
Hey Ken, what up?
I am using your 2-216 and loving it. :D
The think has awesome cooling capacity...

But anyway, it would be very interesting to see the gains with all the different intake and exhaust manifolds...if I only had the money to do it... :(

Are you sure the stock intake manifold is tuned for 6200 RPM? I had heard that a 6500-RPM tuning point equates to about an 8" long runner (valve to plenum). The stock 2G intake runners are much longer then that and the 1G isn't much shorter, at least I don't think it is.
 

dsm156

Probationary Member
23
0
Sep 27, 2002
Salt_Lake_City_UT
Originally posted by NDgsx


No, I just like overkill and pissing off my welder :thumb:



Me too... :D
I figured 321SS would be sufficent though.
 

NDgsx

DSM Wiseman
1,163
3
Jun 10, 2002
Vancouver, Washington
I did the math a long time ago, not sure where I lost the paper. If I get bored maybe I'll do it all again and double check it. That's if I can get the book on manifold design from the UW engineering department again.
 

Speed52257

Probationary Member
7
0
Oct 9, 2002
Muncie, Muncie_IN
I bought this T-25 turbo for my eclipse. The standard manifold won't fit. It's a rectangular shaped outlet. Can anyone tell me which manifold i need to get and also which O2 housing I need to get? The guy I bought the turbo off of said it had standard T3 flanges???

Thanks for the space,
Josh
 

KenTSIII

Proven Member
495
1
May 29, 2002
Indianapolis_IN
Sounds like the T3 flange. You can get the turbonetics manifold for around $450.. or look into one of the tubular manifolds posted above. Also I know that AMS (www.automotosport.com) offers an adapter to go from the stock mitsu flange to the T3 flange.

Good Luck.
 
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