Stainless or factory exhaust manifolds, results inside.

[lwells]

Is this test only going to involve a change in manifold? From what Scooby was saying in an earlier post, he was going to change a number of other items at the same time which will make any comparison useless.

LW.

[GTR32]

John;

Champion for agreeing, well done. Cred to you.

LW;

Scooby also said the exact test would have to be negotiated, preferably with an independant validator like ummm...lets see.... SK! John suggested this would be something you'd do when you were changing turbos etc, which makes sense, so I don't see the problem as long as the baseline is known. Scooby said N1s and dumps etc which is a very common modification route so it should suit a lot of us.

Guys;

Geez, first the Magic/Catco test, now this. We are getting some serious grunt going here, now that's what I call a proper tech forum.

Regards

[lwells]

GTR32: Yes, I know, I have been keeping a close eye on this thread. However, I was hoping for clarrification.

The problem I forsee is: how do you isolate the performance gained from the manifold alone -- which I think most of us are interested in -- from the performance gained from changing turbos, dumps, etc, etc? Those are major modifications in my books. I don't see how you can have a comparable baseline.

As I said, I'm in a position where I need to change the manifolds shortly anyway and would happily voluntier, but like most people I want to change the dumps at the same time which I think would just raise more questions than it answers. People will forever say "oh but he also changed X-Y-Z so that invalidates the result".

Just my 0.02c. Feel free to ignore.

LW.

[GTR32]

LW;

Your point is completely reasonable. The mods Scooby has planned - along the lines of what John suggested - would have to be baselined and a manifold change done.

I'm not sure there's any another way to do it.

Regards

[retrotec]

John, last year you were selling stainless steel high mount exhaust manifolds for the rb25. Have you experienced problems with these and have you tested these manifolds?.

[Boosted Zed]

Yes we have just recently flow tested these adn well not the best and very different in flow figures per runner. As I mentioned earlier in this thread this will be another subject and another thread when we get the stock manifold extrude honed. Carlo got your ears on as on SAU had a stainless one he bought from us and worped and cracked and went back to stock manifold and all good. This was a tuning issue more than anything though and no not from us.

[Scooby]

Geez, a thread full of AJ's (or ex's) and a dodgy ex-copper No wonder the topic has turned to crap.

Hi Geoff;

Heh heh please tell me you're not at DMO aka Forces of Darkness and Misunderstood User Requirements LOL.

John;

Thank you for accepting the challenge. At this stage the only way I can see the test would be worthwhile is if the modifications ie dumps, turbos, tune etc are done and tested with the standard manifold and then the manifold is replaced with yours and retested. I have N1s and will use either CES or Trust dumps with an ecu reburn.

Ideally it would be in conjunction with another workshop so that there can be no suggestion of fudged results down the track, particularly if they exceed expectations.

The payment arrangement if it does / does not work to the expected degree (nothwithstanding it's currently a bit unknown due to the r and d aspect) we should take off-line, and I'll call you to discuss this.

Anyone have comments?

Regards

[GTRgeoff]

Hi Geoff;

Heh heh please tell me you're not at DMO aka Forces of Darkness and Misunderstood User Requirements LOL.

Was at DMO for 4 years, engineering and project managing. Now DTR-A policy and implementation. We make the dark side look like a girl guide picnic. As of tomorrow I officially commence leave IOT become a sly-villian so I really CBF about the whole thing anymore. 20 Years and a pension. MMMmmmm.

[Roy]

In summary - Stainless steel:

1) Excellent heat retention (low thermal conductivity)

2) Durability

3) Strength per unit weight

4) Cosmetics

 

You should probably add that 300 Grade Stainless steels expand a hell of a lot more when hot/cold. This adds to agro when welding the stuff, if not tacked up / fabricated properly it can pull everywhere, and also operating dramas where they can expand and cause stresses in the manifold because, say a 180 degree bend wants to grow at temp, but cant because it is being held rigidly at the head, the turbo/dump.

LOL..no issue is ever black and white, its very much a matter of horses for courses. If you are going to be using stainless pipe in 3.4mm wt then you are losing one of the main points of using a stainless manifold and that the weight saving advantage from being able to use an approx 1.6mm thk tube...but again horses for courses:)

[Ronin 09]

So roy is your manifold cracked or what?

[browny]

The other aspect of SS that I've seen questioned before is it's strength at elevated temperatures. I can't remember exactly what the comment was tho.

[Weq]

Manifold design is a big debate in many car scene's.People have done back to back tests before, ON dyno's. Some with video proof:

http://www.honda-tech.com/zerothread?id=925312

otherwise without:

http://www.honda-tech.com/zerothread?id=1056249 - sr20det gained 68whp with a equal length manifold.

As for stainless steel tubular manifolds being a poor choice between a cast manifold, i think you leave alot to be desired. You must either have a really BAD sample manifold, or are overly exaggerating.

http://members.optusnet.com.au/loxy/car/tu...up/manifold.jpg

http://members.optusnet.com.au/loxy/car/tu...setup/welds.jpg

http://members.optusnet.com.au/loxy/car/tu...p/collector.jpg

Thats 304g stainless steel. Its run for 6 months and just had a bead blast. SHow me the cracks. show me how bad the equal length runners will flow.. the main advanatge of these manifolds is the marge collector and smooth flow it promotes. I can drop this off if u wish to test flow it, but i dont have anything to compare it with.. lol..

[GTRgeoff]

Lots of internal dags and edges on the visible welds. Imagine what it's like where you can't see it. If extrude honing was to be successfully done it would improve it, but from JP's comments it's not possible/feasible.

[Roy]

So roy is your manifold cracked or what?

It turns out a weld in the dump pipe before the cat has given up, and guess what...they are dodgy mig welds that lack penetration, abd at xmas already had a touch up where a weld had a pin prick:)

[lwells]

Bump. Any word on this?

Lucien.

[Boosted Zed]

Anyone know the thickness of the stock GTR cast manifolds? Stainless ones are usually 2 to 3mm and I am sure the cast ones are much thicker but hard to measure?

[lwells]

Yep got them 10 at the moment all polished and sealed nice with fittings for underneath the plenum to match up with all factory hoses, aslo has custom made studs to bolt straight up to lower runners. SAU release price for first ten $1350 each.

John,

Isn't that the GTS-t plenums, not the GT-R manifolds? :confused:

Lucien.

[BOOSTD]

As SK has stated inadvertently flow potential isn't everything. If you increase flow potential only there will be more room for top end power at the cost of response due to gas speed reductions. I think the big money(massive R+D) tuned lengh SS manifolds aim at getting the best combination of port speed tuned lengh and flow for a more specialised result.

[Boosted Zed]

You are missing the point and yes outright flow is not everything, that is why the exstrude honed ones are better as they are more even in flow proven on flow bench test not a Bling Sticker. Also again there is not enough room to make long runners. For twin turbo set up it is tight area smoother thicker cast ones are the go, that is with twin turbo, well made extractors for single turbo may be better although still have the prob of manifolds cracking and radiating a bit more heat. More flow especially if more even is better, obviously. The stainless ones we tested were better than stock as mentioned just not as good as factory cast ones ported and extrude honed. I know many would rather have a bling sticker or mention bling name of a part on their car rather than go fast, just not me.

[Sydneykid]

Personally I prefer the factory exhaust manifold, the best I have seen on an RB20/25DET was the factory Group A R31GTSR. Now that's an exhaust manifold, all thick walled, equal volume, steel pipe that it is.