Zeus,

I am agreeing with you just so you know. Just adding to what you have said and commenting. The article you posted from the engineer at Garrett is very good and is exactly what we have found testing here.

I think the only thing that tlclee has said that is correct is that MOST shops sell what they can get easily OR can make the most profit on. So their sales are driven by that, I am in absolute agreement with that statement. What you will see is I said MOST shops.

I do not feel we fit into that category. The reason is WE are real car guys here. I didn't go to college, I don't write with big words and to be honest, this business is all I have to make a living from. I can't go work as a mechanic as I have no formal training. I can't go work as an engineer, designer or anything else. This is what I do, what I want to do (most days anyway) and to add to all this MY NAME is on our door. That means a lot to me. It means I have to treat customers the way I want to be treated and mostly it means I have to sell parts that work the best. In saying that it means I have spent the last 18 years racing and testing parts for the 4g63 engine, that is all we do. This means if I or someone that works for me recommends you run a 3" downpipe you can bank on the fact that we tested it and there is a reason that is being recommended. Yes, we do sell and occasionally recommend an EVO owner use our 2.5" downpipe but it is rare and only recommended if there is something else restricting the build such as a stock cat that is going to remain in place.

I HAVE done the testing with stock vs. 2.5 vs. 3", I've tested it more than once on more than 1 dyno on more than 1 car. I've seen the results at the track.

2.75" is a retarded size of tubing. It isn't common and I see no reason to argue about a 1/4" of tubing size. There is a point it is going to become a restriction and so is 3".

Right now we have made well over 600 whp on our dyno (for you dynojet guys that is in excess of 720 whp) through our 3" exhaust. We have taken our full 3" turbo back OFF a 500+ whp EVO and found NO gains from doing it, it is just loud as hell.

Another thing I want to point out about downpipes and fitment. Over 3 years ago we built our first 3" exhaust for the EVO's. When doing this I chose to implement a spacer for the lower tie bars to add more clearance for the system. The EVO is a very tight fit for exhaust. The largest problem with fitment is the restriction that a mandrel bender has on the radius vs closeness of the next bend. I have been questioned over the last few years about the spacers and see that people still use NOT using spacers from other companies as a "selling point". I now stand behind our spacers even more than I did 3+ years ago here is why: My idea was as those junk EVO engine mounts get older the engine was going to settle on them anyway, this would mean your exhaust, overtime, would get closer and closer to the tie bars. By using them and including them with our exhaust from the beginning this would never be an issue for our systems. Well guess what? I was right. The last few weeks we have installed our spacers on two seperate EVO's that came through becuase their downpipes that they bought from other vendors are now rattling on their lower tie bars. One other car had the problem that came through here and it was fixed by installing our front motor mount, which lifted the engine back to where it was originally. I knew this would happen from my experience with owning turbo Buicks. The mounts in them sag horribly with age and cause the 3" downpipes to burn into the inner fender well.

We do things for a reason FIRST and for sales running at a close second.

Thanks for your time, I know I can get long "winded".

 

Man a simple question turned into a research paper... I've ruled out 2.5" just can't decide on 2.75" or 3"...

Could someone just make up my mind for me... I need a downpipe ASAP for my IX and there are too many to choose from... I just want one that fits well, doesn't rattle or get too close to my ACD and oilpan and gives me the best gains with stock turbo and 3" HF or TP and Catback??? It can't break the bank either. Thanks!

 

If you want absolutely no fitament problems, I'd say go with the 2.75 inch. It'll be rattle free and provide some nice gains

 

like i said earlier, tanabe for a 2.75 or helix V2 for a 3 inch. i'd go helix since it's a nice, quality made, 3 inch piece that costs less shipped than a tanabe unshipped.

 

the new RSR 3" DP, which deletes cat. it fits the IX with room to spare. i know at least 2 guys running it

 

I like what Dave said because it's all true. If you want to stick with the stock turbo, think about 2.5", it'll be fine. If you want to upgrade your turbo or make some big power run a 3.0". If and when the motor mounts start to sag get a Cusco V2 brace or some spacers. If you happen to find a 2.75" for cheap or your buddy gives you one, go for it!

Cheers,

Gary
Gruppe-S

 

for price i would go with the mr or the espelir, i have the espelir...........


No dp is going to be more than 5hp more than any other....... is it worth to spend an extra 100 bucks on 2hp if that.

 

Gary,

I don't think it was your intention to have people misconstrue, so I wanted to point out that David in no way said that a 2.5" downpipe is fine for a stock turbo (he did say stock cat). Furthermore, all his 2.5" vs. 3" dyno tests in question WERE with a stock turbo... I believe with the smaller 03' turbine housing, but can't recall for sure.

 

So there hasn't been any new data on downpipes on the bigger turbine housing on a IX?

It would be nice to see some new testing of 2.75" vs 3" on a EVO 9 stock turbo...EFIxMR might have a valid point that a 2.75" on an EVO 9 is producing slightly better gains.

 

I have an Espelir JGT500 DP on my IX MR and it fits perfectly and goes well with my Espelir JGT500 Catback and UR Test Pipe. Paid like $185 on www.lancershop.com.

 

some batch of espelir downpipes fit great, but some didn't. Our last batch happened to not fit at all. we had pix so we were allowed to return them.

 

i like the invidia downpipe its loud

 

I have one on the living room floor waiting for me to decide on what to do with it. I will either install it as is or get a little custom work done to it,or I may sell the thing. (I will probably do all three)I am very impressed with the welds, but kind of let down on the flanges. The ID is 76mm, but tapers to 70mm at the exit flange. Also, the flange which connects to the turbo is no more than a steel plate with a 2.5" and 1.75" hole through it with rough non ported edges. On the inside the welds are not ground down, but this may only be at ends, but I doubt it. Except for these, this downpipe is amazing. If you combine what db said about a 2.5" O2 housing being better than the 3" he tested and what the engineer from Garrett said about seperation of exhaust and waste gases and junction of waste and exhaust, then it would seem to me this pipe to be an excellent design. But is it worth almost $1000 shipped..., no way! Go with a TTP or Helix and an ebay O2.

*edit I will post back after the install on wether or not it fits on a IX.

 

While its great that DB did those test, they were done on his 03' evo. Mivec is a different monster.

Also as a reminder, the highest stock turbo pump gas EVO 8 (earlyapex) on the Gruppe-S dyno runs a 2.75".

 

The MIVEC is not going to effec the flow of the exhaust after the turbine wheel. A 3" downpipe is going to make more power than a 2.5 or 2.75" on a car making any decent power at all. It is NOT going to hurt the power of even a low powered EVO. There is NO reason to NOT use a 3" downpipe UNLESS you are going to attach it to the stock catalytic converter. IF you are sticking with the stock cat then use a 2.5" downpipe, otherwise, go with 3".

End of story. Will race for money.