Speed Six Rebuild: Power 4.3 or 4.5?
Discussion
WolfyJones said:
With airbox,decat,exhaust,remap you are looking at 410 Bhp 340 lbft
I am hoping for that without the need to de-cat - too noisy for me.I don't buy the CF air box gains, too. Although I do plan to buy just the CF trumpets, and leave the air box intact, as I suspect it is the trumpets that give any gain, not the actual air box.
Also, to ensure the car gets the best possible gains it can and remain legal (and not too loud), I plan to buy two new cats or sports cats, along with new lambda sensors for the upgrade. Perhaps, if I'm flush, new manifolds ceramic coated (or current manifolds treated), as cabin heat can be a problem...
Am figuring new cats and TB trumpets should do the trick to compliment the 4.3.
chris watton said:
I am hoping for that without the need to de-cat - too noisy for me.
I don't buy the CF air box gains, too. Although I do plan to buy just the CF trumpets, and leave the air box intact, as I suspect it is the trumpets that give any gain, not the actual air box.
Also, to ensure the car gets the best possible gains it can and remain legal (and not too loud), I plan to buy two new cats or sports cats, along with new lambda sensors for the upgrade. Perhaps, if I'm flush, new manifolds ceramic coated (or current manifolds treated), as cabin heat can be a problem...
Am figuring new cats and TB trumpets should do the trick to compliment the 4.3.
What does a standard catted 4.3 make without the extras?I don't buy the CF air box gains, too. Although I do plan to buy just the CF trumpets, and leave the air box intact, as I suspect it is the trumpets that give any gain, not the actual air box.
Also, to ensure the car gets the best possible gains it can and remain legal (and not too loud), I plan to buy two new cats or sports cats, along with new lambda sensors for the upgrade. Perhaps, if I'm flush, new manifolds ceramic coated (or current manifolds treated), as cabin heat can be a problem...
Am figuring new cats and TB trumpets should do the trick to compliment the 4.3.
chris watton said:
WolfyJones said:
What does a standard catted 4.3 make without the extras?
Not sure - am hoping around 400 at the fly - but if it's a bit less, I don't think I'd complain too much.http://www.pistonheads.com/gassing/topic.asp?h=0&a...
WolfyJones said:
What does a standard catted 4.3 make without the extras?
If only there was some kind of resource to find that out...Oh wait, there is!
In answer, the 4.3 seems to average out around 410 bhp 340 lb/ft (fly). The add-ons don't seem to make a large amount of difference.
Don1 said:
If only there was some kind of resource to find that out...
Oh wait, there is!
In answer, the 4.3 seems to average out around 410 bhp 340 lb/ft (fly). The add-ons don't seem to make a large amount of difference.
It also states a 4.3 at 455 Bhp 390 lbft,Oh wait, there is!
In answer, the 4.3 seems to average out around 410 bhp 340 lb/ft (fly). The add-ons don't seem to make a large amount of difference.
WolfyJones said:
chris watton said:
WolfyJones said:
What does a standard catted 4.3 make without the extras?
Not sure - am hoping around 400 at the fly - but if it's a bit less, I don't think I'd complain too much.http://www.pistonheads.com/gassing/topic.asp?h=0&a...
I had always assumed that the original set-up was very well done in the first place - it already has multiple throttle bodies, a huge air filter and decent exhaust system - my view is that perhaps some parts can be made to be as good as new (cats, for example, along with lambdas), and the breathing tweaked for what would best be minimum gains (trumpets)
For the 4.3, as most of the internals are changed for new parts, including new injectors, I figure the engine should perform like brand new, and 400bhp should not be a dream - especially as the standard little 3.6 is good for 350bhp.
I could be wrong, as I am not too mechanically minded, but have done a lot of reading about the pros and cons of this, as it's a lot of money to spend.
ETA - Ideally, I'd like to have Power's new knock ECU done at the same time, but £3k is just too rich for me. £1.5k maybe, but not 3.
Edited by chris watton on Sunday 10th August 21:14
chris watton said:
I have read that thread. My thoughts are that there must have been something catastrophically wrong with those particular cats to rob the engine of a whole VW Lupo's worth of power!
I had always assumed that the original set-up was very well done in the first place - it already has multiple throttle bodies, a huge air filter and decent exhaust system - my view is that perhaps some parts can be made to be as good as new (cats, for example, along with lambdas), and the breathing tweaked for what would best be minimum gains (trumpets)
For the 4.3, as most of the internals are changed for new parts, including new injectors, I figure the engine should perform like brand new, and 400bhp should not be a dream - especially as the standard little 3.6 is good for 350bhp.
I could be wrong, as I am not too mechanically minded, but have done a lot of reading about the pros and cons of this, as it's a lot of money to spend.
ETA - Ideally, I'd like to have Power's new knock ECU done at the same time, but £3k is just too rich for me. £1.5k maybe, but not 3.
What is the general consensus on Lambdas?.. To me it's a load of Hokus pokus, always told need new Lambdas and change them but to be honest the car didn't seem any more thirsty in fact it aways seems just the same but yet I'm told I'm running too rich on fuel? I think they are an easy excuse to squeeze £I had always assumed that the original set-up was very well done in the first place - it already has multiple throttle bodies, a huge air filter and decent exhaust system - my view is that perhaps some parts can be made to be as good as new (cats, for example, along with lambdas), and the breathing tweaked for what would best be minimum gains (trumpets)
For the 4.3, as most of the internals are changed for new parts, including new injectors, I figure the engine should perform like brand new, and 400bhp should not be a dream - especially as the standard little 3.6 is good for 350bhp.
I could be wrong, as I am not too mechanically minded, but have done a lot of reading about the pros and cons of this, as it's a lot of money to spend.
ETA - Ideally, I'd like to have Power's new knock ECU done at the same time, but £3k is just too rich for me. £1.5k maybe, but not 3.
Edited by chris watton on Sunday 10th August 21:14
I've also been told tolerances are so slight between what's seen as ok yet for noticeable difference they would have to be far out?
Incognegro said:
What is the general consensus on Lambdas?.. To me it's a load of Hokus pokus, always told need new Lambdas and change them but to be honest the car didn't seem any more thirsty in fact it aways seems just the same but yet I'm told I'm running too rich on fuel? I think they are an easy excuse to squeeze £
I've also been told tolerances are so slight between what's seen as ok yet for noticeable difference they would have to be far out?
To me, it just makes sense to change the lambdas with the cats - they have been on the car for over a decade with all of that intense heat. I think it would be a false economy not to.I've also been told tolerances are so slight between what's seen as ok yet for noticeable difference they would have to be far out?
chris watton said:
I have read that thread. My thoughts are that there must have been something catastrophically wrong with those particular cats to rob the engine of a whole VW Lupo's worth of power!
I had always assumed that the original set-up was very well done in the first place - it already has multiple throttle bodies, a huge air filter and decent exhaust system - my view is that perhaps some parts can be made to be as good as new (cats, for example, along with lambdas), and the breathing tweaked for what would best be minimum gains (trumpets)
I think you're spot on there. It's easy to say 'your cats rob you of 50/100/200bhp' but it's another matter to remove the cats and see that improvement. As you say the only way that cats would rob you of that much power would be if they'd collapsed. Even in the early days of cats they sapped about 10% but I thought that TVR had got it down to about 2 or 3% which would be much more in line with another statement on that same thread: I had always assumed that the original set-up was very well done in the first place - it already has multiple throttle bodies, a huge air filter and decent exhaust system - my view is that perhaps some parts can be made to be as good as new (cats, for example, along with lambdas), and the breathing tweaked for what would best be minimum gains (trumpets)
s5tvr said:
I can't remember the numbers but I had my 3.6 RR T350 de-catted and though it made a difference that justified doing it, the cats didn't rob me of any more than 10-15 bhp peak.
NB no more than 10 - 15 and 2 to 3% is 7 to 11 bhp.Don1 said:
WolfyJones said:
What does a standard catted 4.3 make without the extras?
If only there was some kind of resource to find that out...Oh wait, there is!
In answer, the 4.3 seems to average out around 410 bhp 340 lb/ft (fly). The add-ons don't seem to make a large amount of difference.
Three which do not state whether they've had a decat, reading 455, 412, and 420 and two which have had a decat reading 410 each so if you were to rely on that info you'd conclude that a decat would ensure a low bhp result
(I know that you've put a lot of effort into that table and it's interesting to read but without more information and a much larger sample size you can't draw any meaningful conclusions.)
Don1 said:
As an ex-scientist, I couldn't agree more. But hamstrung by people being forth-coming means we have to make do with what we have! For example I know that there are quite a few more FFF engines out there than the three listed, but such is the way of the world.
I'll post mine after a visit to SRR - yet to be arranged.And I'm still trying to get hold of some sports cats so that back to back runs of decat vs. sports cats is possible.
as for mine in the chart with 4xx it has had decat cans fitted at that time. made the dyno run just to have a before after comparison of the car otherwise it is not clear what will have what sort of influence. except of that anything bone stock e.g. exhaust. won´t say cat´s steal 50 bhp. guess it will be around 25-30. also 4xx bhp is fly figure and not at the wheels. normally with this kind of thread all cars should go to the same dyno then you will have a proper comparison. a bog standard 4.3 should make around 330 bhp at the wheels with cat´s in place and no other mods. if it´s worth going to 4.5 i don´t know. mine is currently undergoing some mod´s that will lift it to around 450 bhp at the fly but thats it.
gacksen said:
as for mine in the chart with 4xx it has had decat cans fitted at that time. made the dyno run just to have a before after comparison of the car otherwise it is not clear what will have what sort of influence. except of that anything bone stock e.g. exhaust. won´t say cat´s steal 50 bhp. guess it will be around 25-30. also 4xx bhp is fly figure and not at the wheels. normally with this kind of thread all cars should go to the same dyno then you will have a proper comparison. a bog standard 4.3 should make around 330 bhp at the wheels with cat´s in place and no other mods. if it´s worth going to 4.5 i don´t know. mine is currently undergoing some mod´s that will lift it to around 450 bhp at the fly but thats it.
Tell us more! Is it one for this thread or will you wait and tell us more when done? (Be aware though, you will want more - it's a curse!
)will post dyno results once anything is done currently stuck with my datsun project as this need more attention right now. once that is done need to work on the chimaera again as the round trip to southern france / corse and way back to italy left some marks. T350 will be the late winter project and hopefully done feb march next year.
had a visit of the german police yesterday. german guy went to the police in germany after his holliday as he felt my chimaera had been to loud on laggo maggiore swiss side. so german police wanted to see the car
sometimes i feel ashamed of people from my country 
currently stuck with my datsun project as this need more attention right now. once that is done need to work on the chimaera again as the round trip to southern france / corse and way back to italy left some marks. T350 will be the late winter project and hopefully done feb march next year. had a visit of the german police yesterday. german guy went to the police in germany after his holliday as he felt my chimaera had been to loud on laggo maggiore swiss side. so german police wanted to see the car
sometimes i feel ashamed of people from my country Edited by gacksen on Tuesday 12th August 09:44
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