45mm inlet and Plenum base inc 72 mm throttle pot.

[Matthew Poxon]

Interesting discussion this has turned into. I have enjoyed reading the various experiences.

I thought I was the only one who was counting weight. As I am putting on weight I thought it best the car goes on a diet. Here is my very rough list:

Radiator: Radtec Alloy Radiator - saving approx 3-4kg
Battery: 072 (18.5kg) Odyssey PC680 x2 (14kg) - saving 5.6kg
Space saver spare - saving approx 2kg
Tensioner: OEM (1.2kg) JE (200g?) - saving approx 1kg
ACT Carbon Plenum - saving approx 2kg

Future Savings
Inlet manifold - replace for throttle bodies
Starter motor: OEM (8kg) Brise (2.4kg) - saving 5.6kg
Loom - replace with MBE

Probably cancelled this lot out with the equal length manifold now anyway

[QBee]

I think your facebook posts give us a slight clue as to the source of the weight gain, Matthew.
I count my blessings that I am a racing snake myself.

Though she to whom I am related by marriage has been making veiled comments about bra sizes, and she doesn't seem to mean her own

[Classic Chim]

I’ve been looking at seats for sometime
A pair of old lotus seats like Peters re covered will be an instant extra 10 hp equivalent although a bit more padding added might be nice.

That Phazed misses few tricks when it comes to power mods

[900T-R]

Chimaera seats are not that heavy at just under 14 kg apiece. Tuscan seats are at least 4 kg heavier (per side)...

For the Tuscan we have some leather-clad Cobra Buckets (Pro Racer or summat) that weigh about 7 kg in their standard cloth upholstered guise. They are not for the wide hipped, though...

[Classic Chim]

TUSCAN seats heavier, see I’d have thought the opposite for some reason
Just shows what I know

For the ultimate trackday experience and weight advantage decent race type seats with side restraint are probably a must but day by day I’m not so sure.
Easy enough to swap over though.

It’s all power to weight at the end of the day.

I think I’ll try removing the passenger seat and re set cross weights for a competitive trackday

Edited by Classic Chim on Saturday 3rd February 07:24

[Classic Chim]

Going back to heads
Bigger ports and induction = bigger valves = bigger Cam = more overlap and valves being open at the same time for longer.
This is if you are building an engine solely for big power.
This is where my knowledge hits the wall
Purging I think it’s called.

So longer cam duration has both valves open and this can lead to exhaust gases getting drawn back up into the Plenum via the open inlet valve?
The effect must be to dirty the fuel air mixture and cause rough running. This being exasperated at lower revs. Causing it’s own form of shunting.

So you do risk upsetting slow speed manners somewhat if you go for an aggressive cam.
Obvious to some but important to point out.

Cam choice is vital for the characteristics your looking for so a tough decision when used on the road lots.

[QBee]

This is why you have to minimise valve opening overlap if going FI - otherwise all your extra puff goes straight down the waste pipe.

[900T-R]

Classic Chim said:

Cam choice is vital for the characteristics your looking for so a tough decision when used on the road lots.

Can't go wrong with the TVR 885 (on anything bigger than a 4 litre) or alternatively V8D Stealth

[Sardonicus]

900T-R said:

Classic Chim said:

Cam choice is vital for the characteristics your looking for so a tough decision when used on the road lots.

Can't go wrong with the TVR 885 (on anything bigger than a 4 litre) or alternatively V8D Stealth

For all round good driveability and good performance I agree I good compromise both

[Classic Chim]

I was once told the ones Dom orders are cut to his personal requirements and not exactly the same as the 885 you get from Kent Cams,,,,

I’m very happy with the 885 in mine

Edited by Classic Chim on Monday 5th February 17:00

[Sardonicus]

Always presumed that the 885 was one of Powers own spec grinds anyway like the Stealth is V8D's

[Classic Chim]

Stands to reason it’s a closely guarded secret in both cases, don’t blame them to be honest.

Peters lack of vacumn pressure at low revs with his big pistons etc and the inevitable purging that goes on, big Cams do big things and not all in a good way if it’s a city burner

On track a fantastic beast.

[Sardonicus]

Cam overlap/duration bad for this vacuum business

[Classic Chim]

Yeah, and for Peter a proper pain in the butt. Looks like I’ll have to put in a full shift

[phazed]

Vacuum pump kit ordered. Nearly £300 worse off ...............

If it does the biz then all okay.

[Classic Chim]

phazed said:

Vacuum pump kit ordered. Nearly £300 worse off ...............

If it does the biz then all okay.

It’s only money. Your clutch should be light, think of that,,,, mines like a modern Audi, your boys a demon mechanic, slick it is slick I say

[900T-R]

Classic Chim said:

Stands to reason it’s a closely guarded secret in both cases, don’t blame them to be honest.

This is why I ended up buying the standard 885 cam over a custom grind from V8D: the spec is a known while V8D never answered my question about the one they'd be sending me, preferring to ask my card details in reply to me asking...

I know the spec of my engine (at least most of it), I know the spec of what I was taking out, I know what I want from my engine and I'm the one who needs to install and dial in the thing - it's a damn sight easier to decide on a cam if the purveyors aren't being overly secretive about the basic specs. I mean, do they *really* think I am going to take their spec and grind the bl00dy cam myself? Sheesh...

[Boosted LS1]

^ What bit are you going to break?

[SILICONEKID 345HP 12.03]

SILICONEKID 345HP 12.03 said:

Can poor vac cause braking problems ?

[Sardonicus]

SILICONEKID 345HP 12.03 said:

SILICONEKID 345HP 12.03 said:

Can poor vac cause braking problems ?

It harms assistance yes if you dont have vacuum but you would know it a hard pedal and wooden feel (more force needed)

Edited by Sardonicus on Thursday 8th February 00:59