Sc400 Header Install?

JIBBBY · December 13, 2005

Hey I have a technical question - I have a 1992 SC400 Caifornia car and am about to install a set of S@S Headers on it. I understand in order to install the Headers an EGR blocker is needed which I have. My question is by blocking the EGR, and installing the high performance headers, will that cause any problems with the computer or sensing the fuel mix ratio? Can anyone offer me any knowledge on this subject.

Oh and my biggest concern is that I am running a nos system and use it frequently, and I read that blocking the EGR in a USA sc400's can cause the car to run too rich, if so that could mean devistation to my engine. As with nos if the engine runs too rich that means booooommmmm bye, bye engine. I do have an ECU piggyback and I do plan on dyno testing and tuning after install, any advise anyone?

CLightning · December 14, 2005

I see you're from LA. Are these headers C.A.R.B. certified? Just curious.

JIBBBY · December 14, 2005

I see you're from LA. Are these headers C.A.R.B. certified? Just curious.

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This is a California car I am and have been modifying. I am moving to Florida shortly and smog emissions are not a major concern, throwing off my ECU is. These headers are made and sold in Arizona, designed for the sc400. Cost $600, EGR blocker $80. A 15-20hp gain is expected after install. I am one of the few that dare try this header install as far as I can see, but after studying the design of the stock headers I found them to be extremely restrictive in their design and in order to achieve max exhaust flow I must change them out. So these S&S headers are going in one way or another as I try to climb up the horse power latter. I have posted this same question on three forums and no one can answer, unbelievable, is there a lexus mechanic in the house?

bartkat · December 14, 2005

I'm not and expert, but I thought the major concern was running lean. Would you need O2 sims with the headers to fool the ECU so you won't get CEL?

The guys on the following forums are IS guys, but they know nitrous, headers, and boost issues.

Go Fast Stuff

http://my.is/forums/forumdisplay.php?f=88

Go Faster

http://my.is/forums/forumdisplay.php?f=114

Some browsing or searching there should come up with some good info.

JIBBBY · December 14, 2005

I'm not and expert, but I thought the major concern was running lean. Would you need O2 sims with the headers to fool the ECU so you won't get CEL?
The guys on the following forums are IS guys, but they know nitrous, headers, and boost issues.

Go Fast Stuff

http://my.is/forums/forumdisplay.php?f=88

Go Faster

http://my.is/forums/forumdisplay.php?f=114

Some browsing or searching there should come up with some good info.

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Thanks a million I will give it a try!!!!

JIBBBY · December 14, 2005

I noticed you are a sunny California boy yourself and drive a 1993 sc400, curuius do you have anything special going on under your hood of your car?

CLightning · December 15, 2005

I noticed you are a sunny California boy yourself and drive a 1993 sc400, curuius do you have anything special going on under your hood of your car?

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This car is new to me so I don't know what power adders that will make a significant difference other than a rebuilt engine/turbo which require very deep pockets +constant maintainence. Since I'm making this car as my daily driver, I will only go as far putting in a C.A.R.B cert intake, not for power, but just because of its reusable filter. I'll leave the modifying to you guys, which I admire.

JIBBBY · December 15, 2005

I love the stock ride myself, as far as fuel and performance mods go without effecting sound or ride quality would be as follows-

1)Magnaflow catalytic converter- helps exhaust flow as the stock converted gets clogged and restrictive over the years. $150 installed

2)Quietflow mufflers- power and fuel effiecency. $200 installed

3)Dragon Torque converter- all performance no fuel effecieny. $1300. installed

4) Intake which you did

5) Change 2" exhaust piping to 2 1/2 exhaust piping from cat convert to mufflers.

Helps exhaust flow for fuel efficency and performance.

All these will bring your sc to life, all mods will not effect your drive quality but will give you savings at the pump and a good 25-30 hp or so. The Dragon Torque converter is costly but oh so effective in 0-60 times. Something to think about.