Thanks for that ‘tuff’ ! J
Ok, let’s be concise – a header and line will never ‘make’ power J but different headers etc will release power AND torque* differently.
The big, single outlet of the 6-1 header will dump a lot of high-revving-made gas in a short time and therefore good for runs and such. Also why Kameari make large bore primary-piped headers !
Mine are designed primarily for road use whether than be general, normal driving , fast-road or a combination and therefore although they will allow freer flowing gases at high revs, I have three versions to suit different levels of engine size/tune.
But ‘power’ is all at the top end of the rev range and how many of us drive 9/10ths every day and everywhere ?
*coming back to torque….mine are designed to free up that all important factor to overcome the vehicle’s inertia and therefore aid acceleration ! I’ll explain :
Look at any dyno graph read-out and you engine’s torque comes in fairly early compared to power (hp). The earlier that torque engages, the better (faster) your car will accelerate and you use torque for every gear change up ‘til 3-3500 revs which is +80% of the time on the roads.
Makes sense to me to exploit the engine’s torque that you use most of the time rather than be ready for some top end revving one in a while to the detriment of the majority of your driving.
How do mine aid the torque release ?
By having 40 or 42mm interior diameter primary pipes (speak with Eiji of Datsun Spirit who doesn’t like bigger on his engines) to allow a faster flow (and yes, big isn’t always better – that is also true of the rear exhaust line exit and why I’ve reduced the standard muffler from 3” to 2.5”…..and never mind the JDM muffler with 2x 2” exits !) but most importantly the 6x become 2x3 and then 2x and only become 1x as far back as the rear of the gearbox (compare that to the S20 engined OEM and after-market exhausts from Fujitsubo that are twin all the way out).
This pipe number staged reduction allows the exhaust gases to exit asap without interfering with any cylinder firing order !
Those 6-2 which become one before or just under the firewall risk allowing exhaust gases to remount towards the cylinders, effectively choking the engine and reducing power and most especially at lower revs which (see above) is where your toque counts !
Even on a track, you’d notice the difference between mine and a 6-1 – coming out of sharp corners, chicanes, the engine might ‘bog-down’ before the revs build up and you fly off up the track again.
Too many people speak and brag of max power when it’s torque that counts especially from our large cc engines (compared to say, 510s and their four-pots).
Thanks for asking the question and feel free to discuss.
Best regards, Sean
ps of course, let's get real, budgets are also important and most of the MSA kit is inexpensive....all of the Japanese kit is.....mine sits halfway between them and I'm very confident that it matches the performance and certainly the durability of that available in Japan. Also, if anything should break or you damage it - spares (in stainless steel) will always be available.