Which Cams ?

[elliotaw]

I'm at the stage now with my engine build up that I'm ready to fit some cams.

The engine specs :-

lightened 10:1 forged ross pistons
Heads been ported and polished
New manley race valves. +1mm exhausts
Uprated camshaftshop valve springs

I will be running an aftermarket computer and making up a performance header and exhaust system.

I intend on fitting a full set of new billet camshaftshop cams, but I have no experience with cams and need help choosing which one to go for. I spoke to their tech guy a while back and he didnt know if the engine would have enough vacuum for the transmission if you run a very hot cam ?? Anyone have experience with this ?

I dont want an engine that runs rough on idle, but on the same note the car wont be used for everyday driving.

Can anyone offer any advice ?

Elliot

 

[rivmasta]

I can run numbers through EAP if it'll help and give you a rough idea, but you'd best talk to the guys where you're buying it as they'd have real world experience.

do you want torque or a dyno hero? What size extractors (primaries and secondaries) and exhaust are you looking at? how far has the heads been ported, and is it both intake and exh? do you have a tq or hp goal?

I'll try to help based on virtual dyno figures - but, *insert usual disclaimer here*.

 

[elliotaw]

Thanks for the help rivmaster...I called kelford yesterday and had a long chat, went through the engine specs etc and we decided to go for something close to their 207-T1 cam set listed on their webpage :-

http://www.camshaftshop.com/camshafts/view/46/lexus-camshaft

I know very little about cams, so I hope it will be a good choice. My only concern is the amount of vacuum loss for the transmission and brake boosters. Time will tell....

Elliot

 

[rivmasta]

I'll crunch the numbers today and post the results for sh1ts and giggles.

I'll be going with the 207-B: a fair bit lumpier than yours, but then, I dont give a rats about how it idles and the only vaccum line coming out of our plenum is for the ECU.

Matter of fact, I dont care at all how it runs under 3500!

 

[elliotaw]

I'll be running my car on the road as well as the odd track day so i need the car to be driveable at all revs....

Lookin forward to see what figures you come up with

Elliot

 

[GSMnow]

I barely have my car running, and I am already thinking about cams. I know the stock cams are very mild.

My turbo 22RE ran a 268 degree cam (224 @ .050 lift), intake and exhaust with 110 degree lobe centers. At a 900 rpm idle, it only pulled about 15 inches of vacuum. No problem on the brakes and it was still fairly smooth. That would be close to Kelford's 207-C cam.

With the stock ECU and auto trans, I think that would be a bit much. In my case, I need to to run very close to stock for the emissions testing. I can't alter much outside the engine as it will be obvious, and unless the parts are approved by the C.A.R.B. (California air resources board) it is not legal to use on a street car. Cams are hidden in side the motor, so as long as it idles fine and measures clean enough at the pipe, it will sneak by. That limits me to something around 260 degrees or so on the intake (210 @ .050) I wish they could get more lift in that short of a duration.

As far as the auto trans goes though, the Lexus A340/341E transmissions don't read vacuum at all, they use throttle position and output shaft speed to determine shift points. These transmissions even work well in boosted operation, just look at the Supra TT.

Gary M.