Had my Chim on the Rollers - pleased with the result

[Zippee]

Had my Chim up to Surrey Rolling Road on Saturday - usual nervous concerns about what power she'd put out, especially with 54,000 on the clock and being 10 years old. Theres always the concern about cam wear and lack of power as a result.
Really pleased with the output - TVRs own figures at the fly when new were always a little optimistic at 240bhp for the standard 400. Mine made 228.9 at the fly and 180 at the wheels.

No other reason for the post - just wanted to share my good news!

[That Daddy]

Zippee said:

Had my Chim up to Surrey Rolling Road on Saturday - usual nervous concerns about what power she'd put out, especially with 54,000 on the clock and being 10 years old. Theres always the concern about cam wear and lack of power as a result.
Really pleased with the output - TVRs own figures at the fly when new were always a little optimistic at 240bhp for the standard 400. Mine made 228.9 at the fly and 180 at the wheels.

No other reason for the post - just wanted to share my good news!

[jellison]

That is Damn good for a std 4.0.

[f1fx]

mine came out at 226 at the fly . torque was 371 nm. i think will have to get it done again some time ! after a few minor cheep mods

[oggs]

Great news mate

[Zippee]

oggs said:

Great news mate

Cheers Buddy.
As said above - more than happy with the result myself - totally standard engine, just well looked after & properly warmed up.

[Gavstar]

Recently had mine on the RR at Surrey RR and it came out at 234 at the fly and 180something at the wheels, which, same as you, I was very pleased with. I'd started thinking mine was losing power, but I think that's just from getting used to it, and hankering after a 5L.

[jellison]

Gavstar said:

Recently had mine on the RR at Surrey RR and it came out at 234 at the fly and 180something at the wheels, which, same as you, I was very pleased with. I'd started thinking mine was losing power, but I think that's just from getting used to it, and hankering after a 5L.

220 is about right for a good 4.0, 240 for a 4.5 and 250 - 270 for a 5.0 (any more and it ain't std or the rollers are laughably optimistic).

[Gavstar]

jellison said:

Gavstar said:

Recently had mine on the RR at Surrey RR and it came out at 234 at the fly and 180something at the wheels, which, same as you, I was very pleased with. I'd started thinking mine was losing power, but I think that's just from getting used to it, and hankering after a 5L.

220 is about right for a good 4.0, 240 for a 4.5 and 250 - 270 for a 5.0 (any more and it ain't std or the rollers are laughably optimistic).

So mine must be a very good 4.0....

[bigdods]

surrey RR puts my 450 at a rather optimistic 259 at the fly. I know the 205 shown at the wheels is acurate as I got the same figure from the Austec rollers. I never take much notice of the calculated fly figures , the only true test is what comes out at the wheels IMHO.

[Al 450]

jellison said:

Gavstar said:

Recently had mine on the RR at Surrey RR and it came out at 234 at the fly and 180something at the wheels, which, same as you, I was very pleased with. I'd started thinking mine was losing power, but I think that's just from getting used to it, and hankering after a 5L.

220 is about right for a good 4.0, 240 for a 4.5 and 250 - 270 for a 5.0 (any more and it ain't std or the rollers are laughably optimistic).

A stupid question probably but how come the power difference is often quoted as greater between a 4.5 and a 5.0 than between a 4.0 and a 4.5?

3946 -> 4552 -> 4973cc

The jump in engine capacity is less and you are moving away from the thermally most efficient 500cc per cylinder. The 5.0 litres are stroked so surely they won't rev as well as the others which should also be a disadvantage? I know that the 500s had big valve ported heads but so did some of the 450s. Did they also have a higher compression ratio?

[Al 450]

bigdods said:

surrey RR puts my 450 at a rather optimistic 259 at the fly. I know the 205 shown at the wheels is acurate as I got the same figure from the Austec rollers. I never take much notice of the calculated fly figures , the only true test is what comes out at the wheels IMHO.

My 450 showed 218 hp at the wheels with a worn cam at the TVR Power rollers, not sure what the flywheel figures are, does anyone know what the drivetrain losses are in a TVR? I always thought you added around 25%

Can't wait to put it back on the rollers after the rebuild.

[Forthright MC]

thats a fine result Tony, you have good reason to be pleased!

a testament to what a well used and looked after Chim is capable of!

[jellison]

Al 450 said:

jellison said:

Gavstar said:

Recently had mine on the RR at Surrey RR and it came out at 234 at the fly and 180something at the wheels, which, same as you, I was very pleased with. I'd started thinking mine was losing power, but I think that's just from getting used to it, and hankering after a 5L.

220 is about right for a good 4.0, 240 for a 4.5 and 250 - 270 for a 5.0 (any more and it ain't std or the rollers are laughably optimistic).

A stupid question probably but how come the power difference is often quoted as greater between a 4.5 and a 5.0 than between a 4.0 and a 4.5?

3946 -> 4552 -> 4973cc

The jump in engine capacity is less and you are moving away from the thermally most efficient 500cc per cylinder. The 5.0 litres are stroked so surely they won't rev as well as the others which should also be a disadvantage? I know that the 500s had big valve ported heads but so did some of the 450s. Did they also have a higher compression ratio?

450's don't have the Ported heads - don't believ the hype. All this said they are only making about 55bhp/per litre which is pretty pants. Basically jus range rover engine with a cam swap and a bit more Compression (5.0 port a bit over this).