Power limit of Syms/Maxim Works header
 

I'm just wondering if the primary outer diameter of 38.1mm on these headers (I believe they both are the same?) is going to limit my new engine build with a goal of 450-500+ bhp? I think the diameter is even smaller than the stock header?

The sound from these headers is kind of unique which I like but if their limiting the power I'll have to look for something else. They seem to have been quite expensive to buy when new and perhaps a bit of a rarity these days but if they don't perform then it's not much help.

http://www.suruga-performance.com/in...8-impreza.html

When my car last was running in 2011 I got 370 hp on a stock VF28 on E85 with that header, always felt that spoolup was a bit slow though.

The alternative would be GT spec unequal headers or perhaps OEM JDM STI twin scroll. I don't like the sound of other equal length headers on the market.

Hi there

Not sure what is diameter of the GT Spec Headers,but they're fine above yours target,we are run like GT Spec headers at 490bhp and RCM(GT spec replica in many ways) Headers at 555.5bhp and many people run those headers lot higher than we are run

And about the OE JDM STI Twin scroll headers they're been proven too on many cars with higher bhp than you are planning without the issue

SYMS headers not sure,but few people over here run them,but now most of people running GT spec or RCM headers,why you want to go with unequal headers,do you want them due the sound ?

We are run always equal headers without the issue at those power,one thing what can limit yours power is exhaust and engine etc...

Hope this helps

Thanks,Jura

Hi, and thanks for your input

The Tomei/GT Spec and whatever they may be called seem to be 42.7mm OD.

For me the sound is just as, or perhaps more important than getting most power from the header. It just adds so much character to the car IMO. I just feel that many equal length headers sound pretty boring to be honest, the JDM STI TS has a nice rasp above 5k rpm or so though. The Maxim Works/Syms sounds like a mix between unequal and equal length somehow.


I wouldn't swap the Maxim Works I have on the car now but I'm afraid it might be a bit restrictive. But if it would work for say 450 hp then I perhaps could lower my goal a bit.

Hi there

Assume this YT video is yours,sounds good,but not sure if those SYMS/Maxim headers have different sound from GT Spec or RCM what we are run

OE JDM STI Twin scroll sounds nice and this really depends on the exhaust used,last time we are tried JDM STI with Miltek exhaust and sounded just awesome

If they will be bit restrictive,you will see,but I doubt they will be,maybe bit,but I wouldn't expect those headers will restrict a lot

What turbo are you planning to run?

E85 definitely will help with yours bhp target,but this can be depended on turbo used


Thanks,Jura

Yes it's my car, not on the E85 map there though. There are differences in the exhaust tone between different brands of headers, I have a picky ear for that kind of thing I guess :) But of course it also depends on the exhaust, previously I had a Invidia cat back which sounded much more raspy than the Cobra Trackday friendly exhaust in the vid above.

I'm not sure about the turbo, Scoobyclinic of some sort, it depends on the goal really, not that much difference in price between them.

We have E85 on tap here pretty much everywhere so it will probably be used this time also.

Hi there

Agree on that,we are run few brands of the exhaust,but I've always preferred sound of the HKS,they sounds just awesome and Buddy Club has been most nosiest exhaust what we are run,Blitz never been so loud as this,HKS has been somewhere in middle and we are always passed all track day noise limits,with BuddyClub we are not passed,exhaust has been too loud 109,46dB@4500RPM

Revolution track day has been too OK,although on longer drive,has have boomy sound,but sounds good on full tap and should pass every track day

For yours goal I would go with SC42 or MDX321T,we are run only MDX321T and we are made 490bhp on V-power and 20% meth,but SC42 should make yours goal quiet easily too

Wish here is E85,I would run our car only on E85 or 50/50 mixture,but over here in UK,we can dream about the E85

Good luck with yours there

Thanks,Jura

Those headers are way more expensive than the gt spec etc, for that kind of money you can pretty much cover the cost of the Killer B Motorsport headers....!

Better materials, and better design ;)

Smaller primaries doesn't nessecarily mean it will be restrictive as it will keep the gases flowing faster. My killer b units use very small pipework and are still punching out 517hp without the meth ;) with the meth we should be clearing 550....

Yeah it's not like I would pay the full price for that Maxim Works header but it was already fitted to the car when I bought it a long time ago so I might just as well keep it if the smaller primary diameter isn't a problem really.

What's the diameter of the KillerB header? It's seems to be one of the best headers around but I can't find specs of the diameter.

The killer b units are 1" 1/4 if I remember correctly they are very small on the primaries. It says on their website though on the paage about the headers the dismensions :)

Can't find the diameter on their page but I found out on Nasioc that they are 1,5" ID. That's the outer diameter of the primary on my Maxim Works, don't know the wall thickness but I guess it would make an ID of about 35mm then. Not sure how much a difference of 3mm or so makes. I know that the two headers aren't comparable at all otherwise but still interesting to compare.

I believe that is the uppipe/secondary measurement I'm sure the primary from each exhaust port to the collector is around 32mm /1" 1/4

The maxim works are one of the best and proven headers/manifold for the mx5s. I sold mine for £450 when I broke it.
Never heard of subaru ones though.

Sorry for this but what's the limit of std Sti headers on a classic ??
Can get a better uppipe easily and pair/port them at the joints