test pipe vs x-pipe vs RMB
04-05-2012, 03:50 PM
#33
Drifting
04-05-2012, 04:10 PM
#34
oh, oh...I "may" have caused some confusion.
The video I linked http://youtu.be/_vTG3iWkxOI is not the "final" sound I ended up with...I added the rear factory muffler back in because of the rasp between 2100-2400 RPM.
I went back and bolded the sentence in the reply to be sure it is more clear
I didn't post final sound because it just didn't sound as good as it does in person and I was concerned no one would try my idea.
The video I linked http://youtu.be/_vTG3iWkxOI is not the "final" sound I ended up with...I added the rear factory muffler back in because of the rasp between 2100-2400 RPM.
I went back and bolded the sentence in the reply to be sure it is more clear
I didn't post final sound because it just didn't sound as good as it does in person and I was concerned no one would try my idea.
04-05-2012, 06:01 PM
#35
Race Car
^^ Oh, I think you have company. Some get more exploratory, do a search for a thread "pumpkin carving" ...it is S2/S3 centric though... I still say...someone with a torch...make modified/gutted factory pumpkins...!
Last edited by SMTCapeCod; 04-06-2012 at 09:59 AM.
04-06-2012, 06:35 AM
#36
I designed and market the Ritech pipe - and we have sold a lot since I started. There are a lot of iterations, claims, counterclaims and comments to be found on this list. Everyone to his own - and source is probably the deciding factor. If I was buying in the 'States I would go to Roger as he is entirely straight and pleasant character with a good price and no bull****. In Europe please talk to me before making a decision.
I developed these pipes empirically using actual Dyno results and trying all the various forms of X before ending up with the current variation. The Bullets are empty expansion chambers and were suggested by my development guys at the time who were well known in the racing fraternity and they do actually work (otherwise I would not go to the expense and hassle of putting them in). I also tried various forms of X including the very popular Ott type 'siamese split' as I call it and settled with the X I have as it worked better for me and I can put the 02 sensor right in the middle..
The history of X pipes is simple - look up Winston Cup cars on Google and research crossover exhausts. The firing pulses of a 90 degree V8 have two cylinders on the same bank discharging gasses into the manifold in close proximity. A standard manifold cannot get rid of the gasses fast enough so it causes a local backpressure and exhaust inefficiency. By crossing the gas path lower down a venturi effect is caused and each other bank effectively causes as a vacuum to pull the gas away more efficiently. That's the simplified version anyway.
This was only discovered when one driver, who had been consistently faster in a very tightly controlled race environment, had an accident and turned the car over to reveal his secret!
Headers are the next development as they are individual matched lengths so don't suffer the gas 'crashing' They are more complex, expensive and a pain to fit. You have to remove them to get to the clutch as well. However, I have just fitted a set from Paul Anderson to my race car for our right hand drive cars and then adapted the rest of the system - cutting out the X as it should now make no difference (I may put a balance pipe in later) but including the expansion bullets because..... Why not?! I haven't tested them yet but they sound like Armageddon. We'll see. Pics of the std X pipe at link below and I will upload pics of my race development system in the next few days. Richard.
http://www.ritech-systems.com/928_xpipes.html
I developed these pipes empirically using actual Dyno results and trying all the various forms of X before ending up with the current variation. The Bullets are empty expansion chambers and were suggested by my development guys at the time who were well known in the racing fraternity and they do actually work (otherwise I would not go to the expense and hassle of putting them in). I also tried various forms of X including the very popular Ott type 'siamese split' as I call it and settled with the X I have as it worked better for me and I can put the 02 sensor right in the middle..
The history of X pipes is simple - look up Winston Cup cars on Google and research crossover exhausts. The firing pulses of a 90 degree V8 have two cylinders on the same bank discharging gasses into the manifold in close proximity. A standard manifold cannot get rid of the gasses fast enough so it causes a local backpressure and exhaust inefficiency. By crossing the gas path lower down a venturi effect is caused and each other bank effectively causes as a vacuum to pull the gas away more efficiently. That's the simplified version anyway.
This was only discovered when one driver, who had been consistently faster in a very tightly controlled race environment, had an accident and turned the car over to reveal his secret!
Headers are the next development as they are individual matched lengths so don't suffer the gas 'crashing' They are more complex, expensive and a pain to fit. You have to remove them to get to the clutch as well. However, I have just fitted a set from Paul Anderson to my race car for our right hand drive cars and then adapted the rest of the system - cutting out the X as it should now make no difference (I may put a balance pipe in later) but including the expansion bullets because..... Why not?! I haven't tested them yet but they sound like Armageddon. We'll see. Pics of the std X pipe at link below and I will upload pics of my race development system in the next few days. Richard.
http://www.ritech-systems.com/928_xpipes.html
04-06-2012, 09:56 AM
#37
07-09-2012, 05:36 PM
#38
Race Car
A little threadsurrection...
Have an X Pipe and pair of new high-flow cats on their way. I definitely want to keep Cats for both back-pressure and environment-plus the smell.
Car is a 1991 S4. There is already an RMB on the back and the stock mid-resonators.
Will update the O2 sensor.
What type of gains should I expect in power and how much louder?
Right now I love the sound with the cats, mid resonators and RMB.
Thanks in advance,
Michael
Have an X Pipe and pair of new high-flow cats on their way. I definitely want to keep Cats for both back-pressure and environment-plus the smell.
Car is a 1991 S4. There is already an RMB on the back and the stock mid-resonators.
Will update the O2 sensor.
What type of gains should I expect in power and how much louder?
Right now I love the sound with the cats, mid resonators and RMB.
Thanks in advance,
Michael
07-09-2012, 06:19 PM
#39
Race Car
You will get about 25 - 30rwhp when swapping from stock H-pipe/cats to X-pipe with high-flow cats. It will be louder... I have heard a lot of people say it is too loud at that point, and they take the RMB out, especially since the RMB does not add any power.
Dan
'91 928GT S/C
475hp/460lb.ft
Dan
'91 928GT S/C
475hp/460lb.ft
07-09-2012, 06:24 PM
#40
Race Car
You will get about 25 - 30rwhp when swapping from stock H-pipe/cats to X-pipe with high-flow cats. It will be louder... I have heard a lot of people say it is too loud at that point, and they take the RMB out, especially since the RMB does not add any power.
Dan
'91 928GT S/C 475hp/460lb.ft
Dan
'91 928GT S/C
475hp/460lb.ftI so like 25-30 RWHP!
Back in the thread someone (I think Andrew) was contending 10HP for RMB.
If it gets too loud I'll swap my RMB for some stock muffler; could I go for a bigger resonator?
Thanks Dan!
07-09-2012, 06:47 PM
#41
Nordschleife Master
Michael, I would be shocked if you saw 20 rwhp improvement, but I have not done the side by side testing.
The set up you are running right now and like is far to quiet for me... the '88 with the smaller mid resonator and stock cats and RMB is PERFECT IMHO, the larger mid's and RMB (like on my '92 GTS) is just way to quiet for my liking. I think you will strike a great balance with your set up. Might be a touch louder then my '88 S4 with RMB, but I doubt it will be annoying when tooling around and when you want to be a hooligan I think it will be about perfect!
Keep us posted both on power gains and over all sound!
The set up you are running right now and like is far to quiet for me... the '88 with the smaller mid resonator and stock cats and RMB is PERFECT IMHO, the larger mid's and RMB (like on my '92 GTS) is just way to quiet for my liking. I think you will strike a great balance with your set up. Might be a touch louder then my '88 S4 with RMB, but I doubt it will be annoying when tooling around and when you want to be a hooligan I think it will be about perfect!
Keep us posted both on power gains and over all sound!
07-09-2012, 06:51 PM
#42
Race Car
I have seen with my own eyes dyno days with 928's in the double digits from many different years. Most stock S4's would put down ~270rwhp and most S4's with the motorsports X-pipe would put down ~300rwhp. The other 928's would either put down approximately what they were supposed to, or less. Just my observations.
Dan
'91 928GT S/C 475hp/460lb.ft
Dan
'91 928GT S/C
475hp/460lb.ft
07-09-2012, 07:00 PM
#43
Nordschleife Master
Dan, that is AWESOME! My auto S4 puts down 267 or 263...well, Tq and Hp were REALLY close and so those numbers are probably Tq first and Hp second IIRC. I'd love to throw down about 30 more! It would exceed the HP numbers on my GTS's if I did (both are in the 283-286 range) but Tq on the GTS's is just over 305 on both of them.
LOTS of room for improvement on 928's I think with tuning and just a little care on the exhaust side like the X-pipe! GT cams in a GTS and you are ROCKIN' like DOKKEN! Just ask Rog and Jim M! REALLY love to do what those guys have done!
LOTS of room for improvement on 928's I think with tuning and just a little care on the exhaust side like the X-pipe! GT cams in a GTS and you are ROCKIN' like DOKKEN! Just ask Rog and Jim M! REALLY love to do what those guys have done!
07-09-2012, 07:05 PM
#44
Race Car
It's better not to focus on the absolute numbers for two cars on different dynos on different days. If your GTS was at one of the dyno days I mentioned, it would probably have put down closer to ~310rwhp. My post was meant to illustrate the difference in power output between an S4 with and without an X-pipe and high-flow cats.
Dan
'91 928GT S/C 475hp/460lb.ft
Dan
'91 928GT S/C
475hp/460lb.ft
07-09-2012, 07:08 PM
#45
Nordschleife Master
Dan,
Yes, of course! I was comparing my S4 and GTS really, as both those were on the same dyno (but different days...hell, different YEARS!) So, you can't draw direct comparisons of course, but yes, that is quite an improvement and one of these days I will do that to my '92 GTS and probably the '95 as well.
Yes, of course! I was comparing my S4 and GTS really, as both those were on the same dyno (but different days...hell, different YEARS!) So, you can't draw direct comparisons of course, but yes, that is quite an improvement and one of these days I will do that to my '92 GTS and probably the '95 as well.