Fitting a Greddy header onto an SH - Honda Prelude Forum

Joon525 · 06-08-2003, 07:39 PM

From the looks of this picture taken today you SH owners have a MUCH easier time getting the 4th Gen Greddy header to fit your cars. Looks like you just do 2 things

Cut that flange on the secondaries
Cut the collector after the downpipe and shorten it a bit

Thanks to CGR45 for taking the time to meet me today.

GP.45 · 06-08-2003, 09:39 PM

Quote:

Originally posted by Joon525
From the looks of this picture taken today you SH owners have a MUCH easier time getting the 4th Gen Greddy header to fit your cars. Looks like you just do 2 things
Cut that flange on the secondaries

Cut the collector after the downpipe and shorten it a bit

Thanks to CGR45 for taking the time to meet me today.

Thanks, bud - this post is what I've been waiting for for a while - that is exactly what I was planning on doing (fitting a GReddy to an SH, that is)...

But, could you elaborate a little? I understand why you need to shorten the collector slightly. Looking at the stock base vs. SH headers (the collector on the SH is way longer than on the base header, much like the GReddy is), I had suspected that the GReddy would actually be a better candidate for fitting to an SH than it would be for a base model...

...but why would you need to cut the flange on the secondaries? I don't understand.

Also, the O2 sensor bung would have to be relocated, correct?

One more thing - have you measured the pipe diameters for the GReddy and DC headers? What are the differences, i.e., is the Greddy significantly bigger?

Thanks!

CGR45 · 06-08-2003, 10:36 PM

We didn't measure the diameters on the headers. But, to me it seem that the DC header had a bigger diameter. Yes you do have to relocate the O2 sensor bug. Joon525 can elaborate more on this. He knows more about this than I do.

CTPRELUDE · 06-09-2003, 12:06 AM

Thanks for the post. How much harder will the greddy be to fit a base model?

Joon525 · 06-09-2003, 10:36 AM

Quote:

Originally posted by GP.45

Thanks, bud - this post is what I've been waiting for for a while - that is exactly what I was planning on doing (fitting a GReddy to an SH, that is)...

But, could you elaborate a little? I understand why you need to shorten the collector slightly. Looking at the stock base vs. SH headers (the collector on the SH is way longer than on the base header, much like the GReddy is), I had suspected that the GReddy would actually be a better candidate for fitting to an SH than it would be for a base model...

...but why would you need to cut the flange on the secondaries? I don't understand.

Also, the O2 sensor bung would have to be relocated, correct?

One more thing - have you measured the pipe diameters for the GReddy and DC headers? What are the differences, i.e., is the Greddy significantly bigger?

Thanks!

When I say that the flange on the secondaries will probably need to be cut I'm saying so because I'm assuming that for the Base it will be cut and I'm assuming this is the same for the SH.
O2 sensor will probably have to be moved (no biggie)
In the Naturally Aspirated forum I have measurements so just search in there
To fit the Base model you'll have to cut it more, look at my thread in the NA forum for a better idea. I'm getting this thing modded this Saturday and will take more pictures then.

RJs99TypeSH · 06-09-2003, 10:58 PM

Wow, you're right, that does look easy!

The flange (hanger looking plate) isn't used on the 5g, right? Then, basically just cut the last section of pipe so that it meets up with the cat at the correct location (or in terms of the picture, so that it is the same length as the stock piece).

Thanks for the information! Time to go shopping!

R.J.

JDM H22A4 · 06-12-2003, 01:32 PM

looks too easy

fmshaw1971 · 06-12-2003, 01:44 PM

Is it really worth all that trouble? By the time you buy the Greddy and have it cut and welded twice, couldn't you almost get a Mugen for the same price?

Joon525 · 06-12-2003, 04:14 PM

Quote:

Originally posted by fmshaw1971
Is it really worth all that trouble? By the time you buy the Greddy and have it cut and welded twice, couldn't you almost get a Mugen for the same price?

Nah this is still cheaper which is why I think some people want to do this.
In any case if you haven't already heard....I'm selling the Greddy and staying with the header that's currently on the car now.

GP.45 · 06-12-2003, 04:18 PM

Hell, I don't think it would be that expensive to do the mods to fit it. Simple cut and weld, shouldn't cost you more than a hundred or so at any decent muffler shop. GReddy header is about $400. You think it might cost $600 to mod it? I don't.

I'm totally speculating though, I haven't priced it or inquired anywhere. If you've got a friend who's a welder (like an aviation structural mechanic friend of mine), it might only cost you a twelve pack