Are We Still Stuck With the 4-1 Headers?

[Biggie™]

Originally Posted by nigel

http://www.28car.com/acc_dsp.php?h_i...&h_mb_id=83930

will that work on yaris?
its for echo ncp10

There you go, for all those wanting to say they have a 4-2-1 header on their Yaris... 5Zigen

But there's a problem. On a proper 4-2-1 header design, the length of the primaries(tubes coming of the head) need to be far longer then they can be with the current Yaris design. With the limited distance/available space the headers were given, a 4-2-1 header will more than likely not be of as much benefit when compared to a 4-1 OEM/TRD style header.

Just remember... It isn't a coincidence that both the stock Toyota header and the TRD performance header are a 4-1 design.

[Galavoxx]

Originally Posted by Biggie™

There you go, for all those wanting to say they have a 4-2-1 header on their Yaris... 5Zigen

But there's a problem. On a proper 4-2-1 header design, the length of the primaries(tubes coming of the head) need to be far longer then they can be with the current Yaris design. With the limited distance/available space the headers were given, a 4-2-1 header will more than likely not be of as much benefit when compared to a 4-1 OEM/TRD style header.

Just remember... It isn't a coincidence that both the stock Toyota header and the TRD performance header are a 4-1 design.

I agree on this point. The 5Zigen (even if you could get it to fit the yaris, which it wont) is not a true 4-2-1 header. That Zigen looks almost like a hybrid 4-1/4-2-1. The header tubes need to be a certain length to get the most power possible out of the header. This length is going to be different on every car. There's no advantage in having a 4-2-1 header, or any header for that matter, if the primaries (and secondaries) aren't tuned to the proper length. This is why the megan header sucks, IMO. They simply replicated the stock header configuration with a larger diameter tubing. Even a 4-1 header needs tuning and header tuning requires R&D and at least an experienced header builder who knows the effects of primary and secondary tube lengths and what collector configuration(s) to use. Replication of the stock header brings no benifits in the scavenging department, only more air flow. The primaries need to be longer in order to better scavenge exhaust gases. This is the benefit of having the 4-2-1 and as I've said in other threads, there just isn't enough space between the stock header and the exhaust flange to make a true bolt-on 4-2-1. So yeah biggie, I think you're right on. This is why WeaponR hasn't released their 4-2-1 yet. They've had more than enough time. To put a header on this car that actually makes power, the whole exhaust system needs to be replaced. And btw, if any of you vendors are going to offer a full system with cat... please please let me be your guinea pig!!