Specifying a Camshaft for Forced Induction

[Bluebottle]

I re-read an old thread on camshaft design that Rob (V8 Racing) wrote;
Camshaft selection and a bit more...

And was wandering how forced induction affects the principals Rob set out for choosing duration and lca.

[Pasco]

Bluebottle said:

I re-read an old thread on camshaft design that Rob (V8 Racing) wrote;
Camshaft selection and a bit more...

And was wandering how forced induction affects the principals Rob set out for choosing duration and lca.

Hello Hamish

I was under the impression that wild cams and forced induction in our motors was a no no
In other words if i wanted to go down that road i would fist have to get rid of my cam for something milder.

Hows the car doing now fella ?

[Boosted LS1]

You would usually want less overlap so as to keep charge within the cylinder and to prevent it escaping down the exhaust port. That said imo if you wanted a max output engine then some overlap would allow cooling of the exhaust valves and may assist upper end rpm's. Mild street cams work well with blown engines.

[Bluebottle]

Hi ya Paul My custom inlet manifold and gasflowed heads produced bigger numbers than anyone expected, that coupled with a high compression ratio, well...The stock non-crossbolted 5ltr bottom end just ain't meant to take nearly 440lb/ft torque, even after MA dialed it back it was still pushing the laws of physics.

we are having a John Eales engine built to take the power, before I grenade this one. Dulfords are refreshing my old short engine, new bearing shells piston rings etc. So if anyone out there wants a very good 500 Short engine contact me or Dulfords
JE has given me a spec similar to Steve Heaths monster. So whilst i am having an engine spec built i may as well have the cam specced accordingly, only problem is i am getting wildly different cam specs hence this thread.

Mike, do you know the In/Ex duration and lca/FL of the 218 cam which is JE's recomendation? The other two choices i've been given are Piper custom spec.

Edited to work in a bit of free advertising

Edited by Bluebottle on Wednesday 27th August 13:14

[Boosted LS1]

I've used a 218 in a turbo application and it was fine. I had no complaints and liked it. Kent cams will give you the specs if you phone them. If you want a proper turbo cam then get a grind with no overlap. A tr8 racer I know reported that it was mega brill Anything of a mild street nature will work well so I don't think there's any point getting to wrapped up in computations. I've done hours of that for different engines and I'm not sure real progress was made. Just buy something off the shelf and give it a whirl. Because you have capacity don't by a cam to small, this is probably why the 218 is being recommended as it's not to small or to big. It's consistent and middle of the road so a good place to start imo.

[Pasco]

Bluebottle said:

Hi ya Paul My custom inlet manifold and gasflowed heads produced bigger numbers than anyone expected, that coupled with a high compression ratio, well...The stock non-crossbolted 5ltr bottom end just ain't meant to take nearly 440lb/ft torque, even after MA dialed it back it was still pushing the laws of physics.

we are having a John Eales engine built to take the power, before I grenade this one. Dulfords are refreshing my old short engine, new bearing shells piston rings etc. So if anyone out there wants a very good 500 Short engine contact me or Dulfords
JE has given me a spec similar to Steve Heaths monster. So whilst i am having an engine spec built i may as well have the cam specced accordingly, only problem is i am getting wildly different cam specs hence this thread.

Mike, do you know the In/Ex duration and lca/FL of the 218 cam which is JE's recomendation? The other two choices i've been given are Piper custom spec.

Edited to work in a bit of free advertising

Edited by Bluebottle on Wednesday 27th August 13:14

You must have won the lotto you jammy sod

[Bluebottle]

I wish This is all courtesy of a flexible friend...whilst its still flexible

[Pasco]

Bluebottle said:

I wish This is all courtesy of a flexible friend...whilst its still flexible

Good luck mate sounds like it will be a beast

[2Munkys]

Will you be having the CR lowered as part of the rebuild Hamish?

And as the engine is out would it not be wise to extend your friends flexibility to beefing up the gearbox? Or have you done that?

Looking forward to you running it all in in a Helston direction Matey

[Bluebottle]

2Munkys said:

Will you be having the CR lowered as part of the rebuild Hamish?

And as the engine is out would it not be wise to extend your friends flexibility to beefing up the gearbox? Or have you done that?

Looking forward to you running it all in in a Helston direction Matey

Yep lowered compression, internally balanced crank, baffled sump, forged pistons & H beam rods etc. The intension is to run it as is now which will be somewhere between 400-450 bhp for now which is no more than a good cerb pushes through a T5 box. When the gearbox blows, or I find some money from somewhere then I'll get it rebuilt with Quafe internals then we can up the boost .

[grahamw48]

Bluebottle said:

Hi ya Paul My custom inlet manifold and gasflowed heads produced bigger numbers than anyone expected, that coupled with a high compression ratio, well...The stock non-crossbolted 5ltr bottom end just ain't meant to take nearly 440lb/ft torque, even after MA dialed it back it was still pushing the laws of physics.

we are having a John Eales engine built to take the power, before I grenade this one. Dulfords are refreshing my old short engine, new bearing shells piston rings etc. So if anyone out there wants a very good 500 Short engine contact me or Dulfords
JE has given me a spec similar to Steve Heaths monster. So whilst i am having an engine spec built i may as well have the cam specced accordingly, only problem is i am getting wildly different cam specs hence this thread.

Mike, do you know the In/Ex duration and lca/FL of the 218 cam which is JE's recomendation? The other two choices i've been given are Piper custom spec.

Edited to work in a bit of free advertising

Edited by Bluebottle on Wednesday 27th August 13:14

This link posted on the Wedge forum may be of interest.

http://www.btinternet.com/~jon.wolfe/kentcamdata.h...