The cat-bypass "X" crossover
08-27-2002, 12:20 PM
#16
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I have to chime it to back up Norm's claims. I have a dead stock S2 5-speed and it is quite the barn burner. Last year at the fall drive I was behind a modified S4 and every time we got on it I would start to close the gap behind him. I also got into a tangle with a Fiero with an LT1 in it(you do the math). That was scary, but ultimately I started to pull away from him. He couldn't believe it. We conversed at an intersection afterward and he was impressed. However, I did have my A$$ handed to me by a modded Grand National, but that was an expected outcome.
My next project is to attack the exhaust on my car and to add cats to it (has none now). I am not sure what setup I am going to go with, but I not afraid of a couple of high flow cats. Time and again muscle car mags have proven they don't take much power and are worth it.
My next project is to attack the exhaust on my car and to add cats to it (has none now). I am not sure what setup I am going to go with, but I not afraid of a couple of high flow cats. Time and again muscle car mags have proven they don't take much power and are worth it.
08-27-2002, 01:34 PM
#17
928 Engine Re-Re-Rebuild Specialist
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Has anyone gone with the "X" cross-over AND a high flow cat? I'm not even sure if such a configuration would fit.
08-27-2002, 03:29 PM
#18
Actually yes, Louis Ott also makes a full xcrossover/hiflow cat system. Adam B (forum editor) has this setup on his 88S4 AT and it produces good power. Nice tone around town and really roars at WOT.
He was running 14.2sec 1/4 mile times last year I believe...
Normy...please post your slips.....that is one heck of a 1/4mile time...given the factory suggests 15.2 for the Euro 85.??
BTW...Louis ran a 13.5 sec 1/4 mile in his GT a couple of years ago....and he was putting 320hp to the ground at that time....
Later,
Tom
midlman@seanet.com 87s4 AT(13.9sec 1/4miler) 89GT (next week I'll know what the GT does!!)
[quote]Originally posted by Big Dave:
<strong>Has anyone gone with the "X" cross-over AND a high flow cat? I'm not even sure if such a configuration would fit.</strong><hr></blockquote>
He was running 14.2sec 1/4 mile times last year I believe...
Normy...please post your slips.....that is one heck of a 1/4mile time...given the factory suggests 15.2 for the Euro 85.??
BTW...Louis ran a 13.5 sec 1/4 mile in his GT a couple of years ago....and he was putting 320hp to the ground at that time....
Later,
Tom
midlman@seanet.com 87s4 AT(13.9sec 1/4miler) 89GT (next week I'll know what the GT does!!)
[quote]Originally posted by Big Dave:
<strong>Has anyone gone with the "X" cross-over AND a high flow cat? I'm not even sure if such a configuration would fit.</strong><hr></blockquote>
08-27-2002, 05:58 PM
#19
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S2's have advantages and disadvantages. They feel weaker than the 4 valve cars around town, but much stronger at higher RPM's. Porsche quotes 310 hp for this model, but an article on one of these cars in a European magazine said that many mechanics believe 330 hp is a more likely figure. I've added a Borla exhaust, which *might* be good for another 10 or so. Add to this the fact that these cars are typically 3200-3300 lbs, and that I have a 5 speed, and you start to see where the performance comes from. I pulled a 13.8 after several runs at 14.0 on a 70 degree day at near sea level.
N
N
08-28-2002, 02:55 AM
#20
Rennlist Member
Hi all,
As Tom mentioned, I've got the Louie Ott dual cat X-over exhaust. This incorporates Louie's X-over, into two hi - flo cats, into two Bullet mufflers. It uses 2.5" pipes throughout.
It is as quiet as stock at idle, but when you put your foot in it, it really sounds sweet. I really believe I have the Stradivarius of exhaust systems here, and I'm going to be sorry to see it go when I've got my stroker motor complete. The car has a wonderful tone, without any of that open header harshness.
I would encourage anyone who is looking to put a cat bypass or x-over on their shark to contact Louie. He hasn't developed any for the pre-S4 sharks, but its likely he could give you some pointers if you want to have your local shop build one. He has spent countless hours of development time (his dyno sheets when stacked are about 2 inches thick
) in design and placement. I don't believe that all X-over's are created equal, Louie definitely has an excellent product if you are looking for a dual exhaust design.
Before the Ott Exhaust system my car put out 242hp and 274 ft. lbs. After the dual cat exhaust was installed, I turned 266hp and 290 ft. lbs. My first runs show that my car was a little weak to begin with, but the Ott Exhaust definitely freed up some power.
-Adam Birnbaum
'88 S4 A/T
As Tom mentioned, I've got the Louie Ott dual cat X-over exhaust. This incorporates Louie's X-over, into two hi - flo cats, into two Bullet mufflers. It uses 2.5" pipes throughout.
It is as quiet as stock at idle, but when you put your foot in it, it really sounds sweet. I really believe I have the Stradivarius of exhaust systems here, and I'm going to be sorry to see it go when I've got my stroker motor complete. The car has a wonderful tone, without any of that open header harshness.
I would encourage anyone who is looking to put a cat bypass or x-over on their shark to contact Louie. He hasn't developed any for the pre-S4 sharks, but its likely he could give you some pointers if you want to have your local shop build one. He has spent countless hours of development time (his dyno sheets when stacked are about 2 inches thick
) in design and placement. I don't believe that all X-over's are created equal, Louie definitely has an excellent product if you are looking for a dual exhaust design.Before the Ott Exhaust system my car put out 242hp and 274 ft. lbs. After the dual cat exhaust was installed, I turned 266hp and 290 ft. lbs. My first runs show that my car was a little weak to begin with, but the Ott Exhaust definitely freed up some power.
-Adam Birnbaum
'88 S4 A/T
08-28-2002, 11:47 AM
#21
928 Engine Re-Re-Rebuild Specialist
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atb:
If you don't mind me asking, how much did your x-over cost? It sounds like you had a complete exhaust system done, but I'm curious if you know how much just the x-over cost.
BD
If you don't mind me asking, how much did your x-over cost? It sounds like you had a complete exhaust system done, but I'm curious if you know how much just the x-over cost.
BD
08-29-2002, 03:10 AM
#22
Rennlist Member
Big Dave wrote:
>>>>>If you don't mind me asking, how much did your x-over cost? It sounds like you had a complete exhaust system done, but I'm curious if you know how much just the x-over cost.
I believe the Ott X cross over sells for $350, but you should contact Louie directly for a price at louisott@cs.com . The are designed to bolt up to the S4 style exhaust manifolds. If you have an earlier 928, the Ott X won't work, but it would be worth contacting Louie for some insight regarding where to put the X in the system, this can be very critical to optimizing the effect of the X over.
-Adam
>>>>>If you don't mind me asking, how much did your x-over cost? It sounds like you had a complete exhaust system done, but I'm curious if you know how much just the x-over cost.
I believe the Ott X cross over sells for $350, but you should contact Louie directly for a price at louisott@cs.com . The are designed to bolt up to the S4 style exhaust manifolds. If you have an earlier 928, the Ott X won't work, but it would be worth contacting Louie for some insight regarding where to put the X in the system, this can be very critical to optimizing the effect of the X over.
-Adam
