With all of the debate right now as to which aftermarket exhaust manifold is the "best" in terms of price, performance, quality, and reliability for the Evo with a stock turbo, we have been offered the chance to test GT-Spec's all-new bolt-on exhaust manifold for the stock turbo for the Evo 7/8/9.

RallySportDirect has already posted their results with the unit they tested and a gain of 9.4 hp and 6.8 ft/lbs with no tuning was the result on an otherwise stock car with just a turbo-back.

Apparently David Buschur will be testing this manifold as well, and we want to take a stab at it too.

This manifold carries an MSRP of $599, and for the price, we think it will offer significant performance for your dollar.

--------------------------------------------------------------------------------------------------------

We will actually be testing two different versions of this manifold on two different cars.

We will first be testing a unit that incorporates the EGR (anti-lag) ports, and will later be testing a unit without EGR (anti-lag ports) on a different car with similar modifications to the first test car. We DO NOT anticipate any noticeable change in performance at all between the two versions, but it can't hurt to test both, right?

--------------------------------------------------------------------------------------------------------

We received the first manifold (EGR port version) this morning, and hope to have an opportunity to test it doing before and after dyno's within the next week. (time permitting)

As a mini-review of the product before the testing is done, we would like to post our impressions of the piece since receiving it this morning.

Please keep in mind, we have had no personal experience with any other aftermarket manifolds available for this application so we cannot draw a comparison to similarly priced, similarly performing, nor similarly constructed units.

The first thing you will notice with this manifold is that it is not an equal length runner design and that runners 1 and 4 are paired together while 2 and 3 are paired together, as many other manifolds switch these pairings or their location on the flange to the turbo inlet.

It should be noted that this design is the most similar to the OEM cast manifold in terms of the runner location and pairing and in terms of the internal volume of and the length of the runners preventing an excessive decrease in turbine inlet pressure from using tubing that is too long, while still allowing for a significant increase in exhaust gas flow.

Looking at the constuction of the unit, you will notice very high quality materials and craftsmanship. The welding is impecable, the flanges are very precisely machined, the tubing is perfect in every aspect, a the internal surfaces of the tubing where it meets the flanges are as smooth as a baby's bottom. (so to speak).

One thing that really stuck out in my mind when opening the package and removing the manifold was that there were absolutely no metal shavings, shards, nor CNC cutting oil anywhere on this piece. It would seem that great care was taken to clean the unit before it's packaging and ensure that it arrived sure to make a good first impression. (which it obviously did)

Considering the constuction of the unit, the thicknesses of the flanges and tubing, I do not anticipate anyone will have any reliability issues with this manifold. This will also be dependent upon whether or not an aftermarket O2 housing is used and whether or not that O2 housing still uses the support bracket to support the weight of the turbo. Regardless, this manifold appears to have every detail covered and we expect great results from it.

--------------------------------------------------------------------------------------------------------

Pictures:


Full Size: http://www.hostdub.com/albums/MikeFo...5/DSC00449.jpg


Full Size: http://www.hostdub.com/albums/MikeFo...5/DSC00451.jpg


Full Size: http://www.hostdub.com/albums/MikeFo...5/DSC00457.jpg


Full Size: http://www.hostdub.com/albums/MikeFo...5/DSC00458.jpg


Full Size: http://www.hostdub.com/albums/MikeFo...5/DSC00454.jpg


Full Size: http://http://www.hostdub.com/albums...5/DSC00453.jpg


Full Size: http://www.hostdub.com/albums/MikeFo...5/DSC00463.jpg


Full Size: http://www.hostdub.com/albums/MikeFo...5/DSC00461.jpg


Full Size: http://www.hostdub.com/albums/MikeFo...5/DSC00459.jpg

--------------------------------------------------------------------------------------------------------

Again, we intend to perform our testing on these units within the next week, and below is a list of the (performance) modifications of each vehicle on which the testing will be conducted:

EGR (anti-lag) Version
'05 GSR
Injen Turbo-Back (heat wrapped)
K&N Panel Filter
Walbro 255
Forge Wastegate Actuator
Forge Unos MBC set to 22 PSI
Forge Type RS Valve
Custom Dynoflash Tune

Non-EGR Version
'05 GSR
Invidia Down Pipe and Test Pipe (heat wrapped)
Espelir Cat-Back
K&N Panel Filter
Walbro 255
AMS Lower Intercooler Pipe
Samco Upper Intercooler Pipe Hoses
Forge Wastegate Actuator
Forge Unos MBC set to 22 PSI
Forge Evo Recirc. Valve
Custom Dynoflash Tune

We WILL be performing before and after dyno runs with each car and as our vehicle tuning progresses we will continue to provide test data. (with the future addition of cams, mild turbos, and custom tuning.)

"Stay tuned."

 

Unbelieveable!

 

good stuff

 

I have seen Manifolds by Magen, SSautocrome and the likes for my last Car a 95 240SX with an SR in it and by comparison this is much better hands down.

 

FWIW, the most objective means of testing these items is to adjust the post installation A/F to match that of the previous part. Otherwise, we may be looking at changes attributable to changes in A/F (at least to some degree) and not the merit of the part being tested. This is especially true of intakes, cams, exhaust components, and any other mechanical parts that can directly affect A/F . . . especially the too-rich factory A/F settings.

Just FYI.

 

That's a good point, and I will look into it. I know very little about A/F ratio tuning and such (just not my specialty) but I will mention it to someone who knows much more than myself about the subject.

Also, I realize now that I spelled manifold wrong in the thread title! Sorry!

 

wow, good stuff. Cant wait to see what the tests will show..

 

This should be interesting.......

 

That would look nice in my evo

 

The other thing regarding this is to keep in mind that a change in the a/f is usually going to accompany a change in airflow through the engine and to some extent will show that you have either increased or decreased airflow which will of course affect power porduction. It's not as drastic with a maf setup as it would be with a speed density one. But I do agree that ideally you would want to equalize the a/f to show the true results.

 

Yea what ever he said, I second that.

 

That manifold looks really nice. You should do another test with it against the DC manifold. Its almost $200 cheaper and you will most likely get the same if not better results. I installed mine this weekend and couldnt be happier! I also coated it since the stock heatshield is gone now!

 

I had a bad time with a DC manifold on my 240 bought it as soon as they came out and with in 2 months of having it, It was done for the Turbo flange was about to fall off. and how about the thin walls of the DC, i just have a big ? in my mind about the DC and it's longevity but not the fact that it will flow well. I know it will make power and Flow well but if you have to take it off every 4 to 6 Months to send it back and have it fixed for free but have to go with out a car for the week it will take to fix it, it's no deal at that point. just something to think about.

 

how tough is it to get the bolt on/off behind runer #4

 

nice!