When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Looks like a very smart solution to get the length and a cat. Any plans to make a longer race header now?
Originally Posted by MileHigh911
That was the first one they developed. They maxed out gains first, then moved to cat
This is the issue with the name "long tube" headers the inference is that longer is better. Longer is better to a point, but there's a limit to it...
They should be more appropriately called "tuned length" headers as that's what's really going on. You're tuning the length of the primary, steps, diameter etc. to get the expansion waves that occur at each time the tubing changes diameter or merges, to get back to the cylinder when the intake valve opens so that you're pulling air forcefully into the cylinder...
You want them just long enough, but not too long...
Lots of data to get through. We learned a lot about how sensitive the RS is on the dyno, I'm going to get the data compiled and put up for everyone about this hopefully over the weekend!
Originally Posted by usctrojanGT3
If anyone who has the race version and wants to go catted, I might be interested in buying your used race version.
All the race headers we had in stock are sold, 2 installed locally, and 1 shipped to AZ...
Will be 4-5 weeks best case before we have more... and honestly only guys that are selling their cars let the race headers go. They're that good.
Lots of data to get through. We learned a lot about how sensitive the RS is on the dyno, I'm going to get the data compiled and put up for everyone about this hopefully over the weekend!
All the race headers we had in stock are sold, 2 installed locally, and 1 shipped to AZ...
Will be 4-5 weeks best case before we have more... and honestly only guys that are selling their cars let the race headers go. They're that good.
I know where the ones going to AZ are going to....
I wasn't consistent with the graphs and it can be confusing, For the GT3 graphs the headers are the solid line and the stock runs are the dashed line. For the RS it's reversed, headers are dashed line and stock is solid line. Sorry for the confusion. When I get a sec I'll try to fix it so it's consistent...
Please make sure to see our other post on our study on the US spec RS'
991 GT3 Dundon Street (Catted) 434whp peak 991 GT3 Dundon Street (Catted) System (solid) vs Stock (dashed)
991 GT3 Dundon Street (Catted) 26lbft and 23whp at 4500rpm 991 GT3 Dundon Street (Catted) (solid line) vs Stock (dashed line), 26wtq and 23whp at 4500 RPM
991 GT3 Dundon Street (Catted) 30whp max gains 991 GT3 Dundon Street (Catted) (solid line) vs Stock (dashed line) 30whp max gains at 8215RPM
991 GT3RS Dundon Street (Catted) 445whp peak 991 GT3RS Dundon Street (Catted) (dashed line) vs stock (solid): 445whp
991 GT3RS Dundon Street (Catted) 29lbft and 24whp at 4478rpm 991 GT3RS Dundon Street (Catted) (dashed line) vs Stock (solid line) 29lbft and 24whp
991 GT3RS Dundon Street (Catted) 32whp max gains 991 GT3RS Street (Catted) (dashed line) vs Stock (solid line) 32whp max gains
And just for fun a little sibling rivalry...
GT3RS (solid) vs GT3 (dashed) both with Dundon Street Systems 991 GT3RS vs 991 GT3 both with Dundon Catted Systems (RS is solid, GT3 is dashed)
Looks great Jamie. You guys should run the 991 GT3/RS Race headers up on the same dyno now and update your site with the new traces to keep everything consistent...
What loss factor are your predicting for the Dynapak? 15%.
Also, am I correct in pointing out that the catted system does not include the valves for switching the exhaust in and out below 4000 rpm?
Looks great Jamie. You guys should run the 991 GT3/RS Race headers up on the same dyno now and update your site with the new traces to keep everything consistent...
What loss factor are your predicting for the Dynapak? 15%.
Also, am I correct in pointing out that the catted system does not include the valves for switching the exhaust in and out below 4000 rpm?
Thanks Mark!, we did run the Race headers can see the results in the other thread we did, site is in the midst of being updated. I'll likely keep the Dynojet trace of the 991 GT3 we did way back as it's got mileage...
Dynapak 4000 is about 15%, we get 400whp for the 991 GT3, advertised BHP is 468HP SAE corrected, which get's us to about 14.5% loss
The Street (catted) also has valves so it's quite low key around town.
Picture below has it (bypass pipe is missing as the picture was taken during fitment)
10-17-2016, 05:16 PM
