Help me choose a cam

[ChilliWhizz]

Hi Cad, not what you're after but I'm running one of Rob's bespoke cams which he described as 'something between a Stealth and an H404'. The low down torque is OK and the car is very driveable but I think a more 'torquey' cam would see the torque curve 'flatter' with more low down torque (and possibly a higher peak figure) but with a corresponding decrease in peak BHP.....

TBH I've also been thinking of a cam change to get more torque lower down and a 'lazier' drive, as it is the 6k rpm N/A scream is awesome but the local constabulary seem to have a different opinion

[ClassiChimi]

What year is your 450.
whst milage, have you had a compression test done on it Jed

The later 450 engines came direct from Landrover and had slightly better heads, (I think)

Lapping in the valves alone may add some compression and thus power,

Not sure why your graph starts a bit late!
These power curves can only be an estimation of power as we're all using different dyno's on different days,
There's to many variables.

In defence of your engine mine was not as fast before the re build and faster again post MBE ignition,
And considering what those two things cost it effing needs to be
My graph is with Mbe and that includes removal of the AFM so I've already got better and free flowing air direct to the plenum with zero restrictions, it's simply louder on induction roar so it's then bound to produce more power.

I really should have had a Dyno run before I had the Mbe installed, it's probably my imagination but it does feel a lot more responsive and does seem to get more fuel and air in at higher revs so it holds its power curve for longer,,
I hit the limiter and the engine feels like it would Rev far higher and still be pulling hard, it's tailing off over 5500 revs but you can hardly notice it,

So in essence I've got more torque and more bhp that easily uses the available revs.
I bugged Dom about gas flowing the heads and inlet port included in the price of the engine re build some 3 odd years ago, he looked away but I do believe he put his magic on it a touch. I ask him all the time and he just winks.

I

[caduceus]

ClassiChimi said:

What year is your 450.

1997

ClassiChimi said:

whst milage, have you had a compression test done on it Jed

approx 44k miles. No compression test.

Sorry for the tardy response chaps. Been out most of the day. But I did have a nice conversation with a one of the guys at Kent Cams today. Very helpful and very informative. Has left me feeling I need to do some research on cam dynamics and understand fully what all the variables mean and how they affect the engine. Today's chat has got the ball rolling and has whetted my appetite to understand it properly. Then I will go back to either Kent or Piper and get them to make me one with my requirements.

Suffice to say, the 435 cam that was in there is no good. So the 885 (today's modern equiv) is not for me either. Something about too much overlap, which is designed to work at high revs but at the cost of losing some compression at lower rpm. Also the lift and duration are a little too high (284/300 deg duration and 116 deg lift). I need more like 265 or 270 duration and 110 lift, at a rough guesstimate. But I need to do some homework and pick some more brains from various knowledgeable sources before I order.

[ClassiChimi]

Very interesting Jed, cam lobe design and overlap etc is an intriguing subject, keep us informed of your findings, the older I get the more torque I seem to want

[gacksen]

caduceus said:

approx 44k miles. No compression test.

Sorry for the tardy response chaps. Been out most of the day. But I did have a nice conversation with a one of the guys at Kent Cams today. Very helpful and very informative. Has left me feeling I need to do some research on cam dynamics and understand fully what all the variables mean and how they affect the engine. Today's chat has got the ball rolling and has whetted my appetite to understand it properly. Then I will go back to either Kent or Piper and get them to make me one with my requirements.

Suffice to say, the 435 cam that was in there is no good. So the 885 (today's modern equiv) is not for me either. Something about too much overlap, which is designed to work at high revs but at the cost of losing some compression at lower rpm. Also the lift and duration are a little too high (284/300 deg duration and 116 deg lift). I need more like 265 or 270 duration and 110 lift, at a rough guesstimate. But I need to do some homework and pick some more brains from various knowledgeable sources before I order.

maybe give JE or paul at v8 tuner a call. they will know. dyno with the fairly mild JE cam.
as for the duration and lift it would be a Kent H200 / H218 .

Edited by gacksen on Friday 1st July 06:18

[caduceus]

gacksen said:

as for the duration and lift it would be a Kent H200 / H218 .

The H218 is a better cam than I currently have, for me at least. But the duration is a little too high and it would retain power up to the 5k rev mark at the sacrifice of power/torque lower down. The H200 is closer to what I'd want I think. But as I mentioned, I need to research more as there is the timing and ignition element to consider too.

[Paulprior]

When you make a decision could you please share some costs, i am also looking to do the same, with a preferance on Torque, i like the sound of 'Stump Puller'
Paul

[carsy]

I ran a Kent H200 many moons ago on a 3.5 RV8. It ticked over superb and low down running was smoother than a smooth thing. Power was instant from literally no rpm. It did however run out of puff very quickly at the top end. It literally lost all power at about 5k rpm just like a diesel does when revved.

All depends where you want your power and how you drive / rev your car. Low to mid or mid to high rpm. You can sort of have 2/3rds of the rev range but unfortunately not everywhere.

The Kent 218 is sort of mid way with good low down driveability as i suspect the Real Steel Stump puller is.

Have a read here for some more insight.

http://www.pistonheads.com/gassing/topic.asp?h=0&a...

Edited by carsy on Saturday 2nd July 12:21

[caduceus]

Paulprior said:

When you make a decision could you please share some costs, i am also looking to do the same, with a preferance on Torque, i like the sound of 'Stump Puller'
Paul

Will do.

carsy said:

I ran a Kent H200 many moons ago on a 3.5 RV8. It ticked over superb and low down running was smoother than a smooth thing. Power was instant from literally no rpm. It did however run out of puff very quickly at the top end. It literally lost all power at about 5k rpm just like a diesel does when revved.

All depends where you want your power and how you drive / rev your car. Low to mid or mid to high rpm. You can sort of have 2/3rds of the rev range but unfortunately not everywhere.

To be honest, and I know this will sound a little odd, but I like the way turbo diesels make their power. A bit of lag then BOOM, and then out of puff at 5k. It suits my driving style and 'feels' a lot quicker to me. And that's what it comes down to doesn't it. Pub bragging figures and dyno charts mean nowt to me on the open road. The H200 does indeed feel like a contender. But if I can understand enough about cam design and dynamics to allow me to have a bespoke cam made for me, I'll go down that route. If not, either the 200 or 51 that Kent does.

[Matthew Poxon]

TVR Power 885 for me as well. I love the flat torque you get from it and it is not too bad top end either:

[Matthew Poxon]

Toma500 said:

Heres mine another 885 done at the same time as powers MBE ecu swap pre- serp 500 72k precats out
And smoothbore and K&N filter .

That torque curve is unbelievable Paul, what a great result.