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Quote:
Originally Posted by RarlyL8 View Post
...It is difficult to see improved drive-ability on a dyno...
Brian,

Again, I love what you are doing.

I would think there is no reason a proper dyno test could not help document your personal observations about experiencing an increase in pre-boost pull /HP.

It would just require starting the dyno run from something close to 1000rpm. It would not even have to be a full pull.

My hope being there is some type of monitoring or control for changes in AFR's, actual boost achieved, and inter-cooler exit temp's in some way. We all know that 930's can respond significantly to changes in any of these.

If the AFR's and boosted air temps are stable, and there is a notable increase in HP before boost onset, that would document any increase in pre-boost HP and be way--way cool.

As I kind of implied, design can win over concept.

Thus, while we may volley on concepts or theoretical conclusions to some degree, I am not in any way doubting your observations!

Unfortunately there have been so many performance clams made in the name of exhaust over the years...

Even without any tests, if I were building by next 930 at this time, I would probably want a set your headers.


ps, I to never has any problem with heat on my B&B's. I did have to have the Y at the turbo re-welded and this I suspect may have cost me my K29 and may also eaten my early K27HF prototype.
Old 10-30-2009, 04:27 PM
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[QUOTE=911st;4983387]Brian,

Again, I love what you are doing.

I would think there is no reason a proper dyno test could not help document your personal observations about experiencing an increase in pre-boost pull /HP.

It would just require starting the dyno run from something close to 1000rpm. It would not even have to be a full pull.

QUOTE]

You are wrong about your assumption. Only terribly expensive chassis dynos like the car companies use for emissions development and compliance can do what Brian says and he is correct with his off-boost statements.

Local dynos are only good for saying "look - my HP is bigger than yours!" and that isn't accurate as most just grab a peak and come off.
Old 10-30-2009, 08:40 PM
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I do plan to dyno the headers and overlay the graphs but I don't expect to see much. The difficulty I was referring to is that a more smooth torque curve or a torque curve that is slightly more aggressive does not jump out at you on paper due to the scale of the graph.
A good example is graphing a common turbo swap. When I swap a 3LDZ for a K27S and overlay the graphs the change looks rather unremarkable while the driving experience change is HUGE. I circle a small area from 2000-3000rpm and show this to the owner. See this area right here? You now have 100 ft/lb more torque there than before the swap. Doesn't look like much on paper but it is huge on the road.

I do agree with you Keith that we are talking relatively small changes. Headers are not the best bang for the buck but they are an important component to achieve a rounded performance package.

As for heat I have tried GHL and B&B. Neither did as good a job as the stock exchangers. Stock exchanger heat is my goal. It is fair to also note that my car runs cool. It never gets much past 180F and in the winter the oil struggles to hit 160F in off boost driving.
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RarlyL8 Motorsports / M&K Exhaust - 911/930 Exhaust Systems, Turbos, TiAL, CIS Mods/Rebuilds
'78 911SC Widebody, 930 engine, 915 Tranny, K27, SC Cams, RL8 Headers & GT3 Muffler. 350whp @ 0.75bar
Brian B. (256)536-9977 Service@MKExhaust Brian@RarlyL8

Last edited by RarlyL8; 10-30-2009 at 09:57 PM..
Old 10-30-2009, 09:55 PM
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Keep up the good work Mister B!

Old 10-31-2009, 09:01 AM
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