De cat pipes, linked or not?
Discussion
What are peoples opinions on de-cat pipes being linked to balance the system as opposed to just straight pipes?
More power on linked? Different sound?
Mine are currently just the straight type but considering getting a whole new system and may go the linked route?
I know on the cross-plane V8s its common practice to have a 'H' pipe or whatever to link them but on a flat plane engine are the benefits the same?
More power on linked? Different sound?
Mine are currently just the straight type but considering getting a whole new system and may go the linked route?
I know on the cross-plane V8s its common practice to have a 'H' pipe or whatever to link them but on a flat plane engine are the benefits the same?
Edited by high52kojak on Friday 23 October 20:59
Although I have no hard evidence (there never is on engine faults) but based on a discussion with a renowned engine builder of several yrs experience with Tuscan racing inc AJP, a secondary issue raised by the subject of another thread here on PH does highlight the possible best choices of exhaust system design appropriate to the AJP (flat plane) v old style V8 (cross plane).
Other than that, a previous bristol region member suffered a catastrophic failure post fitting linked pipes.
While no relationship between the two events can be confirmed as absolute, in my eyes there is no smoke without fire, so re the links on the other thread explain why/when linked pipes are applicable, I would advise against the fitting of linked pipes on the AJP....stick with the straight throughs.
But that's my own opinion based on what I have read and heard.
Buyer beware.
Other than that, a previous bristol region member suffered a catastrophic failure post fitting linked pipes.
While no relationship between the two events can be confirmed as absolute, in my eyes there is no smoke without fire, so re the links on the other thread explain why/when linked pipes are applicable, I would advise against the fitting of linked pipes on the AJP....stick with the straight throughs.
But that's my own opinion based on what I have read and heard.
Buyer beware.
Allandwf said:
Anyone know where I can buy the linked type of decat for the 4.2? Tried looking up the usual places but just seem to have the straight through pairs.
I got mine from Joo (spitfire4v8) though it was a while ago and I don't kow if he still does hem. If you ask him I am sure he will be able to tell you 
Chuggaboom said:
Although I have no hard evidence (there never is on engine faults) but based on a discussion with a renowned engine builder of several yrs experience with Tuscan racing inc AJP, a secondary issue raised by the subject of another thread here on PH does highlight the possible best choices of exhaust system design appropriate to the AJP (flat plane) v old style V8 (cross plane).
Other than that, a previous bristol region member suffered a catastrophic failure post fitting linked pipes.
While no relationship between the two events can be confirmed as absolute, in my eyes there is no smoke without fire, so re the links on the other thread explain why/when linked pipes are applicable, I would advise against the fitting of linked pipes on the AJP....stick with the straight throughs.
But that's my own opinion based on what I have read and heard.
Buyer beware.
what renowned engine builder? if it's the person I think it is then what he was saying was complete and utter bOther than that, a previous bristol region member suffered a catastrophic failure post fitting linked pipes.
While no relationship between the two events can be confirmed as absolute, in my eyes there is no smoke without fire, so re the links on the other thread explain why/when linked pipes are applicable, I would advise against the fitting of linked pipes on the AJP....stick with the straight throughs.
But that's my own opinion based on what I have read and heard.
Buyer beware.
ks. the linked decats add about 1.5% to the total airflow .. the engine failure they saw caused by a weak mixture would have needed something like a 20% increase in airflow. he was talking out of his arse.Chuggaboom said:
Although I have no hard evidence (there never is on engine faults) but based on a discussion with a renowned engine builder of several yrs experience with Tuscan racing inc AJP, a secondary issue raised by the subject of another thread here on PH does highlight the possible best choices of exhaust system design appropriate to the AJP (flat plane) v old style V8 (cross plane).
Other than that, a previous bristol region member suffered a catastrophic failure post fitting linked pipes.
While no relationship between the two events can be confirmed as absolute, in my eyes there is no smoke without fire, so re the links on the other thread explain why/when linked pipes are applicable, I would advise against the fitting of linked pipes on the AJP....stick with the straight throughs.
But that's my own opinion based on what I have read and heard.
Buyer beware.
I too heard the story, and spoke to the various parties involved, which led me to the non-linked route. Although the cerb probably would have been fine with linked, I thought sods law mine would develop a problem. The thing to bear in mind with the story above is that there are hundreds of cerbs with linked pipes which run perfectly well. I wasn't after outright bhp/torque so wasn't too bothered about a few extra ponies that the linked pipes supply. When Joo fitted the whirlwind, SP exhaust & decats, he also did re-mapped it, this gave me peace of mind that it was running as best it could be. With the Bristol cerb that failed, it could have been a faulty map & the fact that engine failed after the linked de-cats were fitted could be co-incidence. We will never know. I took the owner of the failed engine out in mine last week for a run, which he thoroughly enjoyed. Other than that, a previous bristol region member suffered a catastrophic failure post fitting linked pipes.
While no relationship between the two events can be confirmed as absolute, in my eyes there is no smoke without fire, so re the links on the other thread explain why/when linked pipes are applicable, I would advise against the fitting of linked pipes on the AJP....stick with the straight throughs.
But that's my own opinion based on what I have read and heard.
Buyer beware.
I don't understand why the linked / non-linked work differently even though I've had it explained to me properly
I got my pipes from Matt at Silverstone Performance, who could supply either linked or non linked. He had to get a pair of linked pipes cut and blanked off for me
I too have heard the story that you shouldn't have linked pipes, I was told "The AJPV8 should be treated as 2 separate engines, they need to be kept separate"
However I have am SP system with linked de-cats. SP did a lot of work to get the exhaust system right. ACT do linked systems, Joo recomends linked systems, and all those guys know what they are talking about.
Bottom line...The linked or non-linked debate needs clarifying by an expert, and not discussed based on hearsay and rumour.
However I have am SP system with linked de-cats. SP did a lot of work to get the exhaust system right. ACT do linked systems, Joo recomends linked systems, and all those guys know what they are talking about.
Bottom line...The linked or non-linked debate needs clarifying by an expert, and not discussed based on hearsay and rumour.
I think from my limited reading that the exhaust link changes the vacuum and pulsing and therefore the mix/efficiency in the combustion chamber? I guess this might be where an engine builder rather than a tuner might have concerns? Not that I share their concerns. I dont know enough!
It's probably also important to point out that the idea for linking the pipes was initially proposed by an ex cosworth employee who is well versed in engine development at the highest levels of motorsport, hardly the sort of person you'd expect to propose something fundamentally flawed ...
From what I have read, the flat plane V8 does not need balancing as its basically two straight four pots sharing the same crank. Not sure what effect the unusual 75 degree angle makes though.
A local exhaust manufacturer was suprised to see mine was not balanced, but he is used to doing American V8s.
He makes a very good looking 'X' piece for balancing, something I may be getting done to mine.
A local exhaust manufacturer was suprised to see mine was not balanced, but he is used to doing American V8s.
He makes a very good looking 'X' piece for balancing, something I may be getting done to mine.
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