991s will aftermarket headers give me this much gains??
09-19-2013, 02:34 PM
#31
Drifting
also for anyone reading this thread that WANTS headers, but can't justify the cost, we have a set of dyno time only developement headers that produced the gains in the above dyno chart. We are selling them for a discounted price of $1600 as they are not new. They still come with our industry best 2 year warranty on the HJS sport cats.
09-20-2013, 10:42 AM
#32
Drifting
Hi Chris,
The CEL showed up after about 3-4 cycles, approximately 10 days after the install (I was traveling and didn't drive it much after the install).
I drove yesterday and after the warm-up phase I got the CEL. Attached is a screen shot of the codes we pulled yesterday. Thanks!
The CEL showed up after about 3-4 cycles, approximately 10 days after the install (I was traveling and didn't drive it much after the install).
I drove yesterday and after the warm-up phase I got the CEL. Attached is a screen shot of the codes we pulled yesterday. Thanks!
09-20-2013, 11:58 AM
#33
09-20-2013, 12:19 PM
#34
Drifting
Well, I already have the Fabspeed ones for starters, and I'm happy with the quality. I'm also not convinced that long tube headers will give me more power with this particular engine. And, I don;t think anyone makes them and offers them unless I want to have them custom built by b|b|i. In any case, these high flow cats give me a CEL, so I need to figure out first why that is...
09-20-2013, 10:27 PM
#35
Well, I already have the Fabspeed ones for starters, and I'm happy with the quality. I'm also not convinced that long tube headers will give me more power with this particular engine. And, I don;t think anyone makes them and offers them unless I want to have them custom built by b|b|i. In any case, these high flow cats give me a CEL, so I need to figure out first why that is...
http://www.cargraphicts.com/index.php?id=141356&L=1
They also come with 200 cell cats and their cats are BIG (5" diameter) which surely give better flow and longer service life.
09-20-2013, 11:02 PM
#36
Drifting
I understand that you already bought the header. But since you asked if anyone made the longer tube. Here it is :
http://www.cargraphicts.com/index.php?id=141356&L=1
They also come with 200 cell cats and their cats are BIG (5" diameter) which surely give better flow and longer service life.
http://www.cargraphicts.com/index.php?id=141356&L=1
They also come with 200 cell cats and their cats are BIG (5" diameter) which surely give better flow and longer service life.
09-20-2013, 11:05 PM
#37
This is very basic information that is incorrect. If we are talking about old engines, with fixed cam timing, non variable plenums, ect. then yes usually the shorter primary lengths will give greater gains on the top end.
With these new high compression/direct injection cars and all of the technology designed to give nice, broad, flat torque curves, exhaust backpressure has more of an effect on the powerband.
Here is an updated dyno chart for our 991 Sport Headers - the one on the website is incorrect.
With these new high compression/direct injection cars and all of the technology designed to give nice, broad, flat torque curves, exhaust backpressure has more of an effect on the powerband.
Here is an updated dyno chart for our 991 Sport Headers - the one on the website is incorrect.
Looking at your own dyno chart, torque curve between 3500 - 4500 RPM is dropping. That's where the longer tube headers can help to gain more torque in these RPM range. In fact for street use, we use medium RPM range all the time. So it is more useful to promote torque in this area than try to promote power at top end RPM (by using shorter tube header than OEM) while the OEM cam is still in place so peak HP will not move to higher RPM anyway.
Last edited by exponential; 09-21-2013 at 12:33 PM.
09-23-2013, 10:56 AM
#38
You may call "basic information" but I call it "Basic Fact".
Looking at your own dyno chart, torque curve between 3500 - 4500 RPM is dropping. That's where the longer tube headers can help to gain more torque in these RPM range. In fact for street use, we use medium RPM range all the time. So it is more useful to promote torque in this area than try to promote power at top end RPM (by using shorter tube header than OEM) while the OEM cam is still in place so peak HP will not move to higher RPM anyway.
Looking at your own dyno chart, torque curve between 3500 - 4500 RPM is dropping. That's where the longer tube headers can help to gain more torque in these RPM range. In fact for street use, we use medium RPM range all the time. So it is more useful to promote torque in this area than try to promote power at top end RPM (by using shorter tube header than OEM) while the OEM cam is still in place so peak HP will not move to higher RPM anyway.
Regarding where to promote the power, that is up to the purchaser where he wants the gains to occur, but in our case there are zero losses and significant gains, even down low, with our sport headers, across the entire torque curve.
09-23-2013, 10:57 AM
#39
09-25-2013, 10:45 AM
#40
Drifting
09-25-2013, 12:06 PM
#41
If he did, I would swap back to the factory MLS gaskets and see if the code persists. It should not as like I said earlier, these are Euro Level 5 emissions capable cats.
09-25-2013, 01:03 PM
#42
Drifting
Thanks! I'll swap the gaskets to the stock ones, and see if that will do the trick. Thanks again, Chris.
09-29-2013, 01:41 PM
#43
Drifting
Switched out the fabspeed gaskets to the OEM ones, double checked all the torque specs, codes came back - both banks. Tech pointed out if the gaskets were faulty (or a leak) the primary sensor would have given me a code, and not the secondary. In any case, looks like my cats are bad for whatever odd reason. I'll order 02 sensor spacers and hope this will do the trick otherwise it is back to stock.
10-07-2013, 11:37 AM
#44
You may call "basic information" but I call it "Basic Fact".
Looking at your own dyno chart, torque curve between 3500 - 4500 RPM is dropping. That's where the longer tube headers can help to gain more torque in these RPM range. In fact for street use, we use medium RPM range all the time. So it is more useful to promote torque in this area than try to promote power at top end RPM (by using shorter tube header than OEM) while the OEM cam is still in place so peak HP will not move to higher RPM anyway.
Looking at your own dyno chart, torque curve between 3500 - 4500 RPM is dropping. That's where the longer tube headers can help to gain more torque in these RPM range. In fact for street use, we use medium RPM range all the time. So it is more useful to promote torque in this area than try to promote power at top end RPM (by using shorter tube header than OEM) while the OEM cam is still in place so peak HP will not move to higher RPM anyway.
The long tube are the green lines and produced a small bump in torque from 3700-4000, but produced less torque above this. The curves were very similar though.
10-07-2013, 01:26 PM
#45
I've given up on all aftermarket stuff. No one has the ability to test their stuff like Porsche itself. Why would Porsche use these mods if they were better. Porsches are incredibly well engineered and with all the computers there is no way any aftermarket company is touching my car. I'm going on to my forth 911 and I've tried many mods including autothority chips/RUF parts/pulling the converters with straight pipes/lowering/quaife differentials etc etc. IMHO the only thing thats worth the effort are maybe wheels and tires. You get nothing back for aftermarket changes and possibly even loose money. Any reliability issues i've had have always been related aftermarket stuff. Do what you wish but I'll only put Porsche parts on my Porsche. Especially so with the new ones.