45mm inlet and Plenum base inc 72 mm throttle pot.
Discussion
QBee said:
^^^^^^^^^^ This.
I did the 72mm upgrade and loads of others, but was still 30-40 bhp short of the Dazmobile.
My heads were stage 3, so smaller valves, and nothing else I did made a blind bit of difference while that restriction was in the system. It finally dawned on me that until I upgraded my heads at vast expense I couldn’t gain 20-30 bhp, which I would barely notice.
As a counterpoint, I had standard sized valves in my 4.3, and got 300 PS (296 BHP) @ 6,000 rpm from my engine with upgraded exhaust manifolds including decat pipes, 45 mm ported intake manifold and the big flared trumpets, twin throttle carbon plenum and smooth bore intake hoses, Vectra injectors and - crucially - mapped ignition (123tune). Before mapped igintion I got 274 PS @5,500 from the same configuration so it's easy to see what potential from the breathing mods went unused up to that point. Camshaft was a boggo Piper 285 (contrary to the engine builder's 'bespoke camshaft' claims I did the 72mm upgrade and loads of others, but was still 30-40 bhp short of the Dazmobile.
My heads were stage 3, so smaller valves, and nothing else I did made a blind bit of difference while that restriction was in the system. It finally dawned on me that until I upgraded my heads at vast expense I couldn’t gain 20-30 bhp, which I would barely notice.
).At an earlier stage I had the 72 mm throttle on std cast plenum upgrade, and had blended my std trumpet base. It only made like 257 hp @ 5,800 or so, or par for the course on a freshly rebuilt 4.3 with ported heads, balanced rotating assembly etc. Indeed, everyone I spoke to since, say the larger throttle plate on the standard hotwire plenum is only good for 2-3 hp at the top end, at best...
Now after much deliberation and discussion the intermediate large valves ('stage 3') have gone in rather than the TVR 'big valves' ('stage 4') with a TVR 885 cam and triple throttle carbon plenum, for ~320 hp top whack and - hopefully - a noticeable midrange boost. TBH I feel that's about the most that I'd ever want in a road driven Chim, expecially as I've been bringing the weight down to just under a tonne.
Sounds like replacing the heavy seats will give me more power (:
Ok forget that then, what bits can I chop off the car
as that’s actually a better way to go.
It’s not just about the ultimate numbers produced but the character and where the power is and I too believe 320Bhp and around 355/360torques is more than enough for a road car.
Trackdays for me are restricted by my power, I know what power it’s got and I also know just a little bit more would be great around our tight short circuits and make it a better experience.
It’s about the only time I’ll be using the gains as it’s more than fast enough for a road car already and I rarely thrash it for the sake of it.
Is it worth doing the heads for a trackday once in a blue moon, not really but on the track day I’ll say it is if I could get that 320, not easy by the sounds of it.
Food for thought.
At no point will I use FI even though that’s the logical way to get big power as I’m not looking for big power.
It’s not something I’m interested in or can really afford right now but port matching and smooth air/fuel flow I am
Thanks for the honest opinions
Very interesting the 72mm Plenum only offering up 2/3hp gain very disappointing.
Ok forget that then, what bits can I chop off the car
as that’s actually a better way to go.
It’s not just about the ultimate numbers produced but the character and where the power is and I too believe 320Bhp and around 355/360torques is more than enough for a road car.
Trackdays for me are restricted by my power, I know what power it’s got and I also know just a little bit more would be great around our tight short circuits and make it a better experience.
It’s about the only time I’ll be using the gains as it’s more than fast enough for a road car already and I rarely thrash it for the sake of it.
Is it worth doing the heads for a trackday once in a blue moon, not really but on the track day I’ll say it is if I could get that 320, not easy by the sounds of it.
Food for thought.
At no point will I use FI even though that’s the logical way to get big power as I’m not looking for big power.
It’s not something I’m interested in or can really afford right now but port matching and smooth air/fuel flow I am
Thanks for the honest opinions
Very interesting the 72mm Plenum only offering up 2/3hp gain very disappointing.
This subject seems to applicable to a lot of us at some stage or another.
My chassis refurb is just starting, and along with it a GEMS upgrade. Being as i need to add a trigger to the flywheel and a GEMS cam, it seems logical to rebuild the bottom end at the same time, top hatting the liners and dynamically balancing it all at the same time.....plus a new clutch as a given.
Part of the top hatting inc decking the block, so might as well look at the heads to match up.....then its the valve size and throating.....inlet matching........Its kind of... "in for a penny". If you don't do it at this stage, well, the man maths suggests you'll either never do it, or it will simply cost more to do in the long run, and who wouldn't prefer an engine that's been built up as intended (blue printed), rather than one that gets upgrades strapped on every so often.
It's a difficult one when coming back to the real world and realising the scale of the financial input.....but, as I always tell my customers, is it not best to stretch your budget and be happy, rather just content??
Adrian
PHD Man Maths
My chassis refurb is just starting, and along with it a GEMS upgrade. Being as i need to add a trigger to the flywheel and a GEMS cam, it seems logical to rebuild the bottom end at the same time, top hatting the liners and dynamically balancing it all at the same time.....plus a new clutch as a given.
Part of the top hatting inc decking the block, so might as well look at the heads to match up.....then its the valve size and throating.....inlet matching........Its kind of... "in for a penny". If you don't do it at this stage, well, the man maths suggests you'll either never do it, or it will simply cost more to do in the long run, and who wouldn't prefer an engine that's been built up as intended (blue printed), rather than one that gets upgrades strapped on every so often.
It's a difficult one when coming back to the real world and realising the scale of the financial input.....but, as I always tell my customers, is it not best to stretch your budget and be happy, rather just content??
Adrian
PHD Man Maths
From the replies on this thread I’m sort of wondering if any of it is worth doing.
Daz who has one of the fastest Chims that’s recorded speed time trials is right in saying 1/2 a second is not a lot but forgetting acceleration times for a moment it’s the extra speed over 100 mph where I’d like it to be faster and I need hp to pull it through the air when over 4000 revs in higher gears to achieve that.
I’m basing all this on experience of QBee,Phazed, Ian’s Griff, Daz and Frank and Pete on the strip, all faster than mine. All have higher hp figures but then these cars have higher figures than just about all of us
I couldn’t out drag a Beemer 3 series on track either
enoughs enough !
He was quicker in and out the corners, I went home and changed the brakes and the tyres not much later I was so upset. He wouldn’t do it again I’m pretty sure of that
The Beemer had a role cage, full on track car with similar level driver, but still
So these mods do work when done fully and that’s the simple moral of the story, all or nothing.
Might as well pull the heads off next winter if I’m to go down this road.
Might as well add a new vernier timing gear set while I’m there, , that’s just off the top of my head
I might just leave it well alone.
Those that have heard it agree it runs very smoothly and isn’t that really the ultimate goal for most of us.
Daz who has one of the fastest Chims that’s recorded speed time trials is right in saying 1/2 a second is not a lot but forgetting acceleration times for a moment it’s the extra speed over 100 mph where I’d like it to be faster and I need hp to pull it through the air when over 4000 revs in higher gears to achieve that.
I’m basing all this on experience of QBee,Phazed, Ian’s Griff, Daz and Frank and Pete on the strip, all faster than mine. All have higher hp figures but then these cars have higher figures than just about all of us
I couldn’t out drag a Beemer 3 series on track either
enoughs enough ! He was quicker in and out the corners, I went home and changed the brakes and the tyres not much later I was so upset. He wouldn’t do it again I’m pretty sure of that
The Beemer had a role cage, full on track car with similar level driver, but still
So these mods do work when done fully and that’s the simple moral of the story, all or nothing.
Might as well pull the heads off next winter if I’m to go down this road.
Might as well add a new vernier timing gear set while I’m there, , that’s just off the top of my head
I might just leave it well alone.
Those that have heard it agree it runs very smoothly and isn’t that really the ultimate goal for most of us.
It's a difficult call Alun, as you do have a lovely car that does what it says on the tin and more.
Knowing what I know now, would I turbo my next one? Probably not.
It may have a lot more BHP etc, but it isn't that much faster - as the Dazster says.
That money would have built a swimming pool for the whole family to enjoy.
Knowing what I know now, would I turbo my next one? Probably not.
It may have a lot more BHP etc, but it isn't that much faster - as the Dazster says.
That money would have built a swimming pool for the whole family to enjoy.
SILICONEKID 345HP 12.03 said:
I did not choose my engine , I wanted a 4.6 with standard bits .V8D offered me my engine because some guy put a big depostit down and then pulled out .
All the parts were there ready to be built .
Still dont have a build sheet , gave up in the end .
That’s sAll the parts were there ready to be built .
Still dont have a build sheet , gave up in the end .
t, I’ll swap then you’ll be happy It’s a glorious car altogether
QBee said:
It's a difficult call Alun, as you do have a lovely car that does what it says on the tin and more.
Knowing what I know now, would I turbo my next one? Probably not.
It may have a lot more BHP etc, but it isn't that much faster - as the Dazster says.
That money would have built a swimming pool for the whole family to enjoy.
It’s a funny thing this hp Knowing what I know now, would I turbo my next one? Probably not.
It may have a lot more BHP etc, but it isn't that much faster - as the Dazster says.
That money would have built a swimming pool for the whole family to enjoy.
Unless it’s like 400+ 300 is pretty much as good as 320 as 350 is nigh on as good as 400
Seems the higher you go the less impressed you are. I suppose that’s why Schumacher’s last tlttle winning V10 had 900 hp!
This comes down to two fundermentsl reasons for me
1 I don’t want to get blown off if I do a trackday as I’ll get angry about it, so an inferiority complex
2 because I have a gut feeling freeing up those last few horses at the top end on my engine which even the dyno graph shows it to be restricted would be about right for the car and me. 320 Bhp is not going to be much use on its own but the extra torque combined,,, enough to keep my respectability
Hey it’s all a bit of fun but circuit driving isn’t, that’s serious and the cars got to be fast enough for it or there’s no point.
I’m close to calling it a day with this daily lark,
Car takes on a different meaning depending on how i want to use it
Slowly I’m coming to believe I’ll have to stop putting pointless miles on it,
That day will signify a change in how I get my kicks from it.
Taking it apart and tuning it is just another part of the fun and why I own it as much as I love driving it.
It’s also why I believe it’s the best sportscar out there for ownership interaction with the car.
It’s simple enough for numpties like me
I just need that bit of extra zip at the top end.
Maybe a lightened flywheel could achieve similar
Classic Chim said:
Sounds like replacing the heavy seats will give me more power (:
Ok forget that then, what bits can I chop off the car
as that’s actually a better way to go.
The car as I got it, including a subwoofer with amplifier and a big tool bag, came in at 1043.5 kg at Intrax' scales eith about 40% of a tankful left. This was after an engine rebuild that had some rotating weight taken out (crankshaft & flywheel) but otherwise standard. Having said that, it sits on the OZ split rim wheels that are about 3/4 of a kg lighter apiece than the cast Imolas.Ok forget that then, what bits can I chop off the car
as that’s actually a better way to go.
The four Intrax spring/shock units weighed 10.2 kg, the Billies that came out weighed 14.5 kg : - 4.3 kg
Skinny spare (?? kg) taken out and replaced with OEM-style air compressor/tyre goo thingy (ca. 1.5 kg)
Std 075 type battery: 14 kg. Odyssey PC950 battery: 9 kg. - 5 kg
Std Lucas starter: 8 kg. Brise axial starter: 2.7 kg. - 5.3 kg.
Old amplifier (Caliber CA-2260): 1.85 kg. New amplifier (Pioneer GM-D1004 Class D): 0.55 kg. - 1.3 kg. More weight saved because of discarded wiring.
Rear subwoofer and 6 x 9 speakers (5.6 kg) replaced with pair of 6 x 9" CDT subs (3.2) kg. - 2.4 kg
Radtec alloy radiator: - ca. 3-4 kg
ACT carbon plenum: - ca. 2 kg
OE exhaust manifolds with dustbin catalyst (?? kg) replaced with ACT manifolds & decat pipes
Etc. As you see, it's relatively easy to shed a couple dozen kg by replacing components with higher specified ones, without deleting any trim or comfort items. Most of the above has been done when stuff needed replacing anyway. None of it sounds significant on its own but it all adds up, especially as lots of it was in the front of the car, outside the wheelbase - which has knock-on effects in being able to retain non-PAS steering and the 'narrow' front tyre size, etc.
I’ve just spent the best part of £3000 on my engine mainly the heads and the 3 stage induction package etc. I was told this may yield around 40 to 50 Bhp over a standard engine with a fresh cam etc, this is on a 400 engine.
I decided to try and make the best of what I had and make it the car it should have been when it left the factory, just wake it up a bit and enjoy it.
I mulled over turbo and sc conversions but quickly found out that I would have needed around £6500 to do them justice, a figure I just could not justify.
I decided to try and make the best of what I had and make it the car it should have been when it left the factory, just wake it up a bit and enjoy it.
I mulled over turbo and sc conversions but quickly found out that I would have needed around £6500 to do them justice, a figure I just could not justify.
Belle427 said:
I’ve just spent the best part of £3000 on my engine mainly the heads and the 3 stage induction package etc. I was told this may yield around 40 to 50 Bhp over a standard engine with a fresh cam etc, this is on a 400 engine.
I decided to try and make the best of what I had and make it the car it should have been when it left the factory, just wake it up a bit and enjoy it.
I mulled over turbo and sc conversions but quickly found out that I would have needed around £6500 to do them justice, a figure I just could not justify.
Have you had much time with the car since or is this still in progress? I only ask as I was chatting to Rob at V8D a couple of weeks ago about going down a very similar route with my own 4.0 (their stage 3 heads + induction package) when I replace the camshaft.I decided to try and make the best of what I had and make it the car it should have been when it left the factory, just wake it up a bit and enjoy it.
I mulled over turbo and sc conversions but quickly found out that I would have needed around £6500 to do them justice, a figure I just could not justify.
It appeals to me for the very same reason- getting the car to where TVR reckoned it was power-wise (or perhaps even a touch more) and then enjoying it on the road.
Squirrelofwoe said:
Have you had much time with the car since or is this still in progress? I only ask as I was chatting to Rob at V8D a couple of weeks ago about going down a very similar route with my own 4.0 (stage 3 heads + induction package) when I replace the camshaft.
It appeals to me for the very same reason- getting the car to where TVR reckoned it was power-wise (or perhaps even a touch more) and then enjoying it on the road.
I’m just starting to put it all back together but am hoping to have it up and running by the end of feb.It appeals to me for the very same reason- getting the car to where TVR reckoned it was power-wise (or perhaps even a touch more) and then enjoying it on the road.
Belle427 said:
I’m just starting to put it all back together but am hoping to have it up and running by the end of feb.
Would be great to hear your thoughts on it once it's up and running.
I won't be making a firm decision on mine until the end of this year as I've decided to build the TVR a garage first
Squirrelofwoe said:
Would be great to hear your thoughts on it once it's up and running.
I won't be making a firm decision on mine until the end of this year as I've decided to build the TVR a garage first
Al as you know I have a very similar setup to Simon with the inlet
And I think it’s a worthwhile thing to do
Yes there is 20 bhp more and it’s something to do when there is st on the tv
Don’t rush it get your bits and bobs together and it will come together Nice
Personally I would not pull the head unless you have to that can be a job for another day
I personally would not bother with the trumpets and just go full bore blended then you could be up to 50mm ish
Get your self a long and shot die grinder tools and have a go your self
Your a rubbing pervert at the best of times this is just hard core rubbing
Have it
And I think it’s a worthwhile thing to do
Yes there is 20 bhp more and it’s something to do when there is s
t on the tv Don’t rush it get your bits and bobs together and it will come together Nice
Personally I would not pull the head unless you have to that can be a job for another day
I personally would not bother with the trumpets and just go full bore blended then you could be up to 50mm ish
Get your self a long and shot die grinder tools and have a go your self
Your a rubbing pervert at the best of times this is just hard core rubbing
Have it
jojackson4 said:
Al as you know I have a very similar setup to Simon with the inlet
And I think it’s a worthwhile thing to do
Yes there is 20 bhp more and it’s something to do when there is st on the tv
Don’t rush it get your bits and bobs together and it will come together Nice
Personally I would not pull the head unless you have to that can be a job for another day
I personally would not bother with the trumpets and just go full bore blended then you could be up to 50mm ish
Get your self a long and shot die grinder tools and have a go your self
Your a rubbing pervert at the best of times this is just hard core rubbing
Have it
Least you got one thing right And I think it’s a worthwhile thing to do
Yes there is 20 bhp more and it’s something to do when there is s
t on the tv Don’t rush it get your bits and bobs together and it will come together Nice
Personally I would not pull the head unless you have to that can be a job for another day
I personally would not bother with the trumpets and just go full bore blended then you could be up to 50mm ish
Get your self a long and shot die grinder tools and have a go your self
Your a rubbing pervert at the best of times this is just hard core rubbing
Have it
This is the plan really. I’m in no position to pull it apart yet anyway.
Blended base, saves a few quid on trumpets but won’t that risk loosing torque ?
I like a to polish me rocket so I think I might have a talent for it
I don’t consider that to expensive,,,, 10 years ago when I had an income to speak of.
Why drive the economy down
A lot of work and some risk goes into head work so it’s not what I’d call profiteering at that price.
And it stays done.
Something as simple as valve seats and getting them accurately installed has its dangers
getting a good seal isn’t as simple as it sounds either.
Good heads are worth there weight in my book
Why drive the economy down
A lot of work and some risk goes into head work so it’s not what I’d call profiteering at that price.
And it stays done.
Something as simple as valve seats and getting them accurately installed has its dangers
getting a good seal isn’t as simple as it sounds either.
Good heads are worth there weight in my book
900T-R said:
The car as I got it, including a subwoofer with amplifier and a big tool bag, came in at 1043.5 kg at Intrax' scales eith about 40% of a tankful left. This was after an engine rebuild that had some rotating weight taken out (crankshaft & flywheel) but otherwise standard. Having said that, it sits on the OZ split rim wheels that are about 3/4 of a kg lighter apiece than the cast Imolas.
The four Intrax spring/shock units weighed 10.2 kg, the Billies that came out weighed 14.5 kg : - 4.3 kg
Skinny spare (?? kg) taken out and replaced with OEM-style air compressor/tyre goo thingy (ca. 1.5 kg)
Std 075 type battery: 14 kg. Odyssey PC950 battery: 9 kg. - 5 kg
Std Lucas starter: 8 kg. Brise axial starter: 2.7 kg. - 5.3 kg.
Old amplifier (Caliber CA-2260): 1.85 kg. New amplifier (Pioneer GM-D1004 Class D): 0.55 kg. - 1.3 kg. More weight saved because of discarded wiring.
Rear subwoofer and 6 x 9 speakers (5.6 kg) replaced with pair of 6 x 9" CDT subs (3.2) kg. - 2.4 kg
Radtec alloy radiator: - ca. 3-4 kg
ACT carbon plenum: - ca. 2 kg
OE exhaust manifolds with dustbin catalyst (?? kg) replaced with ACT manifolds & decat pipes
Etc. As you see, it's relatively easy to shed a couple dozen kg by replacing components with higher specified ones, without deleting any trim or comfort items. Most of the above has been done when stuff needed replacing anyway. None of it sounds significant on its own but it all adds up, especially as lots of it was in the front of the car, outside the wheelbase - which has knock-on effects in being able to retain non-PAS steering and the 'narrow' front tyre size, etc.
That’s a serious weight loss on an already light car. The four Intrax spring/shock units weighed 10.2 kg, the Billies that came out weighed 14.5 kg : - 4.3 kg
Skinny spare (?? kg) taken out and replaced with OEM-style air compressor/tyre goo thingy (ca. 1.5 kg)
Std 075 type battery: 14 kg. Odyssey PC950 battery: 9 kg. - 5 kg
Std Lucas starter: 8 kg. Brise axial starter: 2.7 kg. - 5.3 kg.
Old amplifier (Caliber CA-2260): 1.85 kg. New amplifier (Pioneer GM-D1004 Class D): 0.55 kg. - 1.3 kg. More weight saved because of discarded wiring.
Rear subwoofer and 6 x 9 speakers (5.6 kg) replaced with pair of 6 x 9" CDT subs (3.2) kg. - 2.4 kg
Radtec alloy radiator: - ca. 3-4 kg
ACT carbon plenum: - ca. 2 kg
OE exhaust manifolds with dustbin catalyst (?? kg) replaced with ACT manifolds & decat pipes
Etc. As you see, it's relatively easy to shed a couple dozen kg by replacing components with higher specified ones, without deleting any trim or comfort items. Most of the above has been done when stuff needed replacing anyway. None of it sounds significant on its own but it all adds up, especially as lots of it was in the front of the car, outside the wheelbase - which has knock-on effects in being able to retain non-PAS steering and the 'narrow' front tyre size, etc.
50 odd lb is significant.
More power to weight better cornering and braking ability
That’s quite some achievement
320/350 = fast car
I like it
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