Why Doesn't Any Company Make A Header For The 5SFE Options

[CyberCT]

I have been browsing this forum for quite some time and have noticed that NO COMPANY make a header for the 2.2l 5sfe. SSAutochrome was about to but then people backed out (and yes, I have seen claims of their poor quality with some products. Fortunately this header wasn't bad. There was one or two instances where they did crack or break though in the MR2 community, and that's about it).

I had three MK II MR2s with the 5sfe. I also had the SSAC header on one of them. Let me tell you the performance improvement was noticable right away. It was almost like night and day. More pull and it ran quicker through the gears.

When I had to put the stock exhaust manifold back on for inspection, the car ran much slower, easily noticable.

Now, the NA MR2 weighs in at @ 2650 lbs. The 94-99 Celica GT hardtop weighs in at @ 2450 lbs, correct? A good header would probably make it quicker in a line than the MR2, which felt good in a line.

Is there atleast a header in the works from a reputable aftermarket company?


I'm probably going to be buying a 6th gen celica in the near future as my new daily driver. Is there any place where I can see the yearly updates they did to the celica to fix problems from the previous year? Like for example, in 93, the MR2 fixed some electrical problems or quirks, and upgraded the suspension and other things. Is there a list like this for the 6th gen celicas?

[darksecret]

One of the main causes for the high torque rating is because the 5SFE has some pretty long intake runners, which in turn increase torque numbers, the restrictive head and long IR make for higher torque with lower horsepower, it's been proven time and again. If you could modify the current runners you would lower torque but increase the horsepower potential, or you could rebuild the motor with forged pistons and rods, give the head some mean work, get some high profile cams and boost it, you'll have a beast, but of course $$$. I have realized that the head is the most restrictive part of the entire engine and it's actually pretty beefy to be aluminum. The main reason nobody builds parts for the Celica is because it is a fairly rare car compared to a 240SX and Civic (not to mention when the car was popular the import scene was still small and most americans couldn't tell you what a WRC is), the 5SFE may not have a lot of potential as is, but it really isn't much to make it a beast, if we could get the aftermarket on our side. Also cars like the Corolla and Prizm, 5SFE had the Camry and MR2, I don't think that was the reason.

This post has been edited by darksecret: Jun 13, 2005 - 10:57 AM

[Kwanza26]

One of the main causes for the high torque rating is because the 5SFE has some pretty long intake runners, which in turn increase torque numbers, the restrictive head and long IR make for higher torque with lower horsepower, it's been proven time and again. If you could modify the current runners you would lower torque but increase the horsepower potential, or you could rebuild the motor with forged pistons and rods, give the head some mean work, get some high profile cams and boost it, you'll have a beast, but of course $$$. I have realized that the head is the most restrictive part of the entire engine and it's actually pretty beefy to be aluminum. The main reason nobody builds parts for the Celica is because it  is a fairly rare car compared to a 240SX and Civic (not to mention when the car was popular the import scene was still small and most americans couldn't tell you what a WRC is), the 5SFE may not have a lot of potential as is, but it really isn't much to make it a beast, if we could get the aftermarket on our side. Also cars like the Corolla and Prizm, 5SFE had the Camry and MR2, I don't think that was the reason.
[right][snapback]298334[/snapback][/right]

That is a reason... but that's not THE reason. The problem with the 5SFE making n/a power is the bottom-end. The rods are relatively short, considering it has a full 5mm taller stroke than the 3S, yet the rods' lengths are only about a mm difference (5S vs 3S)... High horsepower, small displacment engines typically have fairly long rods, keeping a good rod/stroke ratio and maintaining good piston dwell time, allowing better combustion, longer compression, and allows for faster revolutions with less internal stress (less piston movement). The 5SFE, with shorter rods, has less piston dwell, but allows for better intake and exhaust velocity at mild speeds... basically it can take larger gulps because the piston has to move more. No matter what you do to the head, the cams, the intake set-up, etc... the basic stroke design is gonna limit the way the engine makes torque. This is the MAJOR reason why I don't think an n/a 5SGE build is a very bright idea (refer to older posts). Little things such as intakes, headers, exhausts... increase efficiency only on a very small scale and are small-time mods for an n/a motor.

You gotta understand the basics of how one part of the engine affects the other if you really want to make n/a power. Even with headwork, bolt-ons, cams, the basic stuff just to open up the engine's potential, you gotta understand that the engine's geometry greatly affects how much potential power can be made. That's why you don't see a lot of n/a mods for the bigger 4 bangers, especially if they're not as popular. If you want bolt-on power... go turbo.

Check out Jim Snodgrass's (http://www.jimsnodgrass.com/dyno.htm) page to see what he did to his 5SFE and then see how much power he actually made. He has the highest whp out of all the n/a 5SFE's I've seen, but even then his powerband looks exactly the same as it did before. Goes to show it's not easy to change an engine's characteristics with bolt-on mods.