Tremonti

Hey guys, just wondering... Do you think that Megan will come out with headers for the Is350? I saw on their site that they made them for 250's. It would be a great time for them to get serious on headers considering mazzuri isn't in buisness anymore. Also, if you have their headers for the 250 please give a little review.

g0tpersian

Yeah I posted a thread about this a little bit ago. They probably won't. The mid pipe is a good investment, that is if you're looking for sound.

Tremonti

Well according to what people got out of their mazzuri headers, there's also a large amount Of horsepower that can be gained so I'm after that too

Kurtz

iTrader: (1)

I thought the Mazzuri headers he made for the 350 actually gained 0 horsepower?

(there was speculation they gained some torque, but the one dyno posted was problematic IIRC)

Tremonti

Oops good call kurtz, I meant torque... But sound is a big factor too of course...

g0tpersian

Just to let you know, the exhaust manifold for the is350(according to a friend of mine who has made and is making a professional IS drift car) is pretty much designed like headers. And according to him, it would be pointless to get headers for your car for any kind of performance.

So, I wouldn't invest in headers for power. He also told me that he did something with the stock exhaust pipe that gave him 17hp on the dyno. I'll have to figure out what it was and post it on here.

As for the headers, pretty much a waste of money. If you want SLIGHT power/sound, straight pipe your car or take off the cats with a custom exhaust kit.

L-S-D

iTrader: (-1)

i still want the megan mid pipe.. but i cant see my self spending 500 bucks in a metal pipe lol...

Kurtz

iTrader: (1)

You should find out. Because if true you friend gained more power with his home-made mod than any professional exhaust company with an actual R&D department has managed on the IS350 with an entire exhaust system.

Tremonti

"He also told me that he did something with the stock exhaust pipe that gave him 17hp on the dyno. I'll have to figure out what it was and post it on here." Seriously if you could find out what/how he did it.(if true) PLEASE tell us! that would be epic.

g0tpersian

Yes, I'm well aware.

I'll talk to him again for sure. I was like :-O NO WAY!? And he said YES WAY.

So, I'll let you guys know.

Gernby

iTrader: (1)

I don't believe there is 17 HP to be gained with any header-back exhaust mod. I also suspect this IS drift car builder really hasn't looked at the OEM exhaust manifolds if he thinks they are designed like headers. They are really designed more like the manifolds that you see on a stock 1980 V6 Chevy pickup.

g0tpersian

He built the drift car that crashed a little while ago. I don't know too much about the drift team he works for. All I know is his driver owned the car he pretty much built. His name is Scott Dodgion.

I don't know. I'll swing by his shop this weekend, and see what he says.

g0tpersian

sorry for the double post.

He built this car. He's in the article:
http://speedhunters.com/archive/2009...e86-turbo.aspx

And that's the lexus he built at his shop
http://www.driftpro.com/spd_metal_works.html

combfilter

iTrader: (3)

Actually the v1 version of the Mazzuri headers showed good tq gains (which i'll take any day over hp). The v2 (which is the version i tested didn't change anything). The main issue was that certain ECU's on certain years of the IS (including mine) were not happy with the o2 sim. You can read the last like 6 pages of the mazzuri thread on here, or I think there is more info on my.is

The stock manifold isn't great btw. I have pictures of it on that thread.

Kurtz

iTrader: (1)

You mean like this dyno chart you posted?

https://www.clublexus.com/forums/3634655-post951.html

Peak loss of 3 hp, and peak gain of 3 torque with the mazzuri headers.

Anything left of 4k is unreliable thanks to the twitchy auto transmission sadly...


I agree torque is terrific, but the proven gains from the header really weren't.

The V1 dyno that showed a "lot" of torque gain is here:
https://www.clublexus.com/forums/3465236-post490.html

But sadly, again, much to the right of 4000 rpms the gains remain in the single digits, with the "big" gains being before the dyno test really started (unless you want to suggest the torque curve remains almost totally flat from about 3000-4300 with the headers and it was at WOT that whole time)




The best way to really test the gains, since no easy solution for the dyno problem was available, and an engine dyno would be insanely costly for this testing, would have been to test em on a 1/4 mile track. Swapping em on/off timely would have been a challenge, so I suppose you might have to try as identical as possible weather (or close with a correction) at the same track... but a solid trap speed gain with the headers would be a lot easier to trust than guessing why 90% of the gains vanish in the entire range the dyno can be trusted in.


I suppose it's all a moot point unless someone fixes the O2 sim issue while developing a new header... (or figures out some way to make a shorty header that retains the O2s while showing worthwhile gains)