Help me choose a cam

[caduceus]

I have a 4.5 which is currently in bits during a resto, which took longer that expected (long story).

Before the resto the car was pushing out 261bhp and 299lbs ft. It has larger valves, but not big valve. So the larger valves and a bit of porting has given the car decent figures but appears to have moved the torque a bit further up the rev range, which is about right, right? More flow - peak torque moves up? That's my understanding, but prepared to be put right (this IS pistonheads after all). It is running a standard 500 cam as all 4.5's have.

In the 4.3 Griff I had years ago, I remember the torque being more prominent and being lower down, which I like. Can I move (and hopefully increase) the torque lower down with a different cam? Or am I stuck with that kind of delivery now with the valves and porting?

Does anyone know of a cam that could do what I want? I will give Kent and Piper a call tomorrow and pose the scenario and see what they say, but I thought I'd run it by you guys first.

Thanks
Cad

[caduceus]

Pupp said:

MC1 is a torque monster but might be very close to what you have - have a look at some of the Real Steel offerings too

I'll Google it. Thx.
I'm getting my springs, followers, etc from Real Steel. Will get the cam there too if they have the one I need. But have a feeling I'll be needing to go to Piper/Kent direct for something. Time will tell.

[caduceus]

Pupp said:

Are you factoring in mapping work/cost if thinking of something very different Cad?

Haven't looked that far down the road yet Gary. Trying not to spend too much on the engine as the bodywork/re-spray is going to eat up most of my budget. I'm hoping I can just install a new cam and set up the timing, and that's it.

[caduceus]

Thanks for the replies all.
I had a little chat with Piper cams yesterday and the chap recommended this cam saying it should move the peak torque a bit lower down, which is what I'm after.


Will give Kent a ring today, and Real Steel for their offerings.

I'm not after crazy BHP, just more torque and coming in earlier. But with the medium big valves I already have, I'm not sure I'm going to get what I ideally want. As more flow equates to more bhp and torque higher up the rev range. Apparently...

[caduceus]

This is the dyno I had done before the resto



As you can see, peak torque is at 4k revs. As I don't like revving the nutts off any engine (one reason why I didn't like the ajp in the Cerb) I'd prefer getting the most ooomph lower down the range. Not bothered about it running out of puff earlier either.

One question - why does the dyno measurement only start at 2150 revs?

[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.

[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.

[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.