Chimaera 5 litre valve sizes
Discussion
Pretty much Calculator time - mine are 1.63" and 1.4"
43 and 37 translate to 1.69" and 1.46".
Thanks gents for the info.
I think therefore that mine are the standard 4.6 heads (ported to stage 3) on my V8D 5.0. So this is probably the bottleneck in getting more air into my cylinders, as I have the bigger AFM, bigger injectors, bigger plenum and 45mm crumpets.
Thinking time
43 and 37 translate to 1.69" and 1.46".
Thanks gents for the info.
I think therefore that mine are the standard 4.6 heads (ported to stage 3) on my V8D 5.0. So this is probably the bottleneck in getting more air into my cylinders, as I have the bigger AFM, bigger injectors, bigger plenum and 45mm crumpets.
Thinking time
t off a shovel? gruffalo said:
Yep, if it won't suck it push it in.
Cheap and reliable these days.
That sounds like advice from the "Dear Deirdre" column of PH.....Cheap and reliable these days.
And there was I, always going to stay normally aspirated....
Three hours with Alexdaredevilz in the car yesterday has taught me two things:
1. The Chimaera is a good place to get a sore throat trying to hold a conversation with a friend on the motorway and
2. 'Garrett' isn't only the word for the place where Harry Potter was created...
QBee said:
Calculator time - mine are 1.63" and 1.4"
43 and 37 translate to 1.69" and 1.46".
Thanks gents for the info.
I think therefore that mine are the standard 4.6 heads (ported to stage 3) on my V8D 5.0. So this is probably the bottleneck in getting more air into my cylinders, as I have the bigger AFM, bigger injectors, bigger plenum and 45mm crumpets.
Thinking time
The 1.63 and 1.4 that you have Anthony are actually one step up from standard size valves about 1.5mm Some people call these big valves as yes they are bigger. The beauty of using these is that they can be made to fit onto the standard valve seat, although they dont leave much meat on the seat.43 and 37 translate to 1.69" and 1.46".
Thanks gents for the info.
I think therefore that mine are the standard 4.6 heads (ported to stage 3) on my V8D 5.0. So this is probably the bottleneck in getting more air into my cylinders, as I have the bigger AFM, bigger injectors, bigger plenum and 45mm crumpets.
Thinking time
If you want the TVR big valves 37 and 43mm you need new seats machining in and this is where it gets expensive both for the seat work and the valves themselves. These go up by approx 1.5mm again from the ones you have now.
I`ve heard going to the TVR big valves from standard can give you approx 30bhp. This will only be seen at 6000rpm mind and with the right cam and porting. You aint going to see 30bhp at lower rpm`s. So possibly another 15bhp for you Anthony as your already half way there.
I priced up these valves with Chesmanns last year for mine and it was about £850 for the machine work and the valves. I would have had to tidy up the ports myself aswell. I`ve stuck with standard valves for now and got 296bhp with a Kent 214 cam.
carsy said:
The 1.63 and 1.4 that you have Anthony are actually one step up from standard size valves about 1.5mm Some people call these big valves as yes they are bigger. The beauty of using these is that they can be made to fit onto the standard valve seat, although they dont leave much meat on the seat.
If you want the TVR big valves 37 and 43mm you need new seats machining in and this is where it gets expensive both for the seat work and the valves themselves. These go up by approx 1.5mm again from the ones you have now.
I`ve heard going to the TVR big valves from standard can give you approx 30bhp. This will only be seen at 6000rpm mind and with the right cam and porting. You aint going to see 30bhp at lower rpm`s. So possibly another 15bhp for you Anthony as your already half way there.
I priced up these valves with Chesmanns last year for mine and it was about £850 for the machine work and the valves. I would have had to tidy up the ports myself aswell. I`ve stuck with standard valves for now and got 296bhp with a Kent 214 cam.
I have nothing to add to this If you want the TVR big valves 37 and 43mm you need new seats machining in and this is where it gets expensive both for the seat work and the valves themselves. These go up by approx 1.5mm again from the ones you have now.
I`ve heard going to the TVR big valves from standard can give you approx 30bhp. This will only be seen at 6000rpm mind and with the right cam and porting. You aint going to see 30bhp at lower rpm`s. So possibly another 15bhp for you Anthony as your already half way there.
I priced up these valves with Chesmanns last year for mine and it was about £850 for the machine work and the valves. I would have had to tidy up the ports myself aswell. I`ve stuck with standard valves for now and got 296bhp with a Kent 214 cam.
............... 
Carsy wrapped it up nicely 
I have the semi BV's fitted same as QBee Sardonicus said:
carsy said:
The 1.63 and 1.4 that you have Anthony are actually one step up from standard size valves about 1.5mm Some people call these big valves as yes they are bigger. The beauty of using these is that they can be made to fit onto the standard valve seat, although they dont leave much meat on the seat.
If you want the TVR big valves 37 and 43mm you need new seats machining in and this is where it gets expensive both for the seat work and the valves themselves. These go up by approx 1.5mm again from the ones you have now.
I`ve heard going to the TVR big valves from standard can give you approx 30bhp. This will only be seen at 6000rpm mind and with the right cam and porting. You aint going to see 30bhp at lower rpm`s. So possibly another 15bhp for you Anthony as your already half way there.
I priced up these valves with Chesmanns last year for mine and it was about £850 for the machine work and the valves. I would have had to tidy up the ports myself aswell. I`ve stuck with standard valves for now and got 296bhp with a Kent 214 cam.
I have nothing to add to this If you want the TVR big valves 37 and 43mm you need new seats machining in and this is where it gets expensive both for the seat work and the valves themselves. These go up by approx 1.5mm again from the ones you have now.
I`ve heard going to the TVR big valves from standard can give you approx 30bhp. This will only be seen at 6000rpm mind and with the right cam and porting. You aint going to see 30bhp at lower rpm`s. So possibly another 15bhp for you Anthony as your already half way there.
I priced up these valves with Chesmanns last year for mine and it was about £850 for the machine work and the valves. I would have had to tidy up the ports myself aswell. I`ve stuck with standard valves for now and got 296bhp with a Kent 214 cam.
............... Carsy wrapped it up nicely I have the semi BV's fitted same as QBee Mine is 300 bhp with a stealth cam. Given the differences between runs on the same rolling road on different days, never mind different rolling roads on different days, mine is making what yours is. So am I right to deduce that the valve size is the limiting factor on the induction side?
I am not prepared to spend even modest amounts just to gain 15 bhp, even though I regularly hit 6000 rpm on track days - law of diminishing returns. The car drives very nicely about town, on country roads and on the race track, and when it and I are having a good day on track, we surprise ourselves how much speed we can carry around the corners. More speed would be gained by fitting some better tyres for starters. My knackered R888s are only fit for the bin (there's actually no tread at all on the front tyres now), as are my Federal 595s.
If I can get out of the corners significantly faster then I might invest in a turbo for the straights, as an alternative to spending the same amount on better heads, and then the same again on a better induction manifold. I couldn't care less about under-bonnet bling, as anyone who has seen under my bonnet (and winced) knows.
mk1fan said:
You need a blower 
Or a T car
It's a nice thought Stewart, but I don't need either, as my car is faster than its driver at present. But on a good day the driver is getting to be a closer match, and I am just thinking ahead like we all do. Or a T car
100 extra bhp for the long straights of circuits like Bedford, Spa, Donington, Silverstone, Thruxton is definitely of interest. At present I find myself writing "to do" lists or thinking about my work schedule on long straights.
As for the T car, well, if I was starting again with 4 times the budget, and was buying a TVR then an LS-engined Tuscan would feature a long way up my list.....competing with the Cerbera, Noble, Aston V8 Vantage and so on.
But I am happy with my Chimaera.
QBee said:
I am not prepared to spend even modest amounts just to gain 15 bhp
This is why i didnt spend and stuck with the standard valves. 15-20bhp at 6000rpm your not really going to notice it. I recon with a Stealth cam i would have got well over 300bhp even with dinky valves. But me personally i like the low down grunt, so much infact i`ve been considering the Stump puller cam. Something to give me as much as possible from 1k to 4.5k rpm which is where mine spends 95% of its time. If i tracked my car well thats different and i would be chasing numbers.
If you are looking for a serious power hike that you will really notice and that represents excellent value for money then yes FI is the way. Go for it Anthony.
QBee said:
That sounds like advice from the "Dear Deirdre" column of PH.....
And there was I, always going to stay normally aspirated....
Three hours with Alexdaredevilz in the car yesterday has taught me two things:
1. The Chimaera is a good place to get a sore throat trying to hold a conversation with a friend on the motorway and
2. 'Garrett' isn't only the word for the place where Harry Potter was created...
If you want to stay normally aspirated and you want to reverse the tables on the 911's then you need a Cerbera;-)And there was I, always going to stay normally aspirated....
Three hours with Alexdaredevilz in the car yesterday has taught me two things:
1. The Chimaera is a good place to get a sore throat trying to hold a conversation with a friend on the motorway and
2. 'Garrett' isn't only the word for the place where Harry Potter was created...
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