NA vs Turbo cams

[IJ.]

Shaeff: If you look at the graphs in the "Cams make a difference on the dyno" thread the stock cams seem to level off at around 5000 rpm while the aftermarket ones continue to make power!

I'm assuming he didn't change anything else related to the upper rpm limit other than the springs required for the new cams!

I always thought the crank was out limiting factor until I read the other thread!

 

[Idealsupra]

Shaeff: If you look at the graphs in the "Cams make a difference on the dyno" thread the stock cams seem to level off at around 5000 rpm while the aftermarket ones continue to make power!

I'm assuming he didn't change anything else related to the upper rpm limit other than the springs required for the new cams!

I always thought the crank was out limiting factor until I read the other thread!

im pretty sure you arent referring the cams manny used to the NA cams? BIG difference

 

[IJ.]

I believe one pull was with stock cams and the next with the aftermarket cams with both curves on the same sheet?

pic pinched from Manny's post (if this is a problem let me know)

 

[bkubisht]

Can anyone shed some light on this?

Aust delivered supra (MA70)
intake open 6deg BTDC close 54deg ABDC
ex open 54deg BBDC close 6deg ATDC

Aust delivered Cressida (MX83)
intake open 6deg BTDC close 40deg ABDC
ex open 53deg BBDC close 3deg ATDC

DEFIANT: OK, so there's quite a difference between the supra and cressida intake cams, and I think it tends to be the valve timing on the intake side that has greatest affect on power curve location. (quoting my old engine rebuilding professor) Closing 14 degrees early should be very significant. Are the cam specs you gave a comparison of turbo vs NA, or supra vs cressida?

SHAEFF: I didn't mean the NA cam would enable you to rev sky high. Just that it would extend the power curve when you're up beyond redline.

 

[Idealsupra]

I believe one pull was with stock cams and the next with the aftermarket cams with both curves on the same sheet?

pic pinched from Manny's post (if this is a problem let me know)

ok yeah...so he got great returns from the aftermarket cams.... but you wont see ANYTHING like that by simply putting in an intake cam from a NA... no way no how

 

[IJ.]

Ideal: You've lost me here!

I was pointing out to Shaeff that the stock cams level off at 5000 ish as he'd posted that he thought the limiting factor was the crank and stock cams would go higher....

I used Manny's results to illustrate this showing that stock stops making power at 5000 and aftermarket cams keep climbing.

 

[Idealsupra]

Ideal: You've lost me here!

I was pointing out to Shaeff that the stock cams level off at 5000 ish as he'd posted that he thought the limiting factor was the crank and stock cams would go higher....

I used Manny's results to illustrate this showing that stock stops making power at 5000 and after market keeps climbing.

i know..i was just pointing out to anyone reading the thread that what you posted was not a dyno from stock turbo cams to stock NA cams.... it was simply to keep people from, gettnig confused

 

[IJ.]

Ahhh ok I thought I'd made that clear when I posted "Aftermarket cams"

 

[shaeff]

Ideal: You've lost me here!

I was pointing out to Shaeff that the stock cams level off at 5000 ish as he'd posted that he thought the limiting factor was the crank and stock cams would go higher....

I used Manny's results to illustrate this showing that stock stops making power at 5000 and aftermarket cams keep climbing.

woah, i was on a completely different base than you... i was saying that the cams arent what limit the redline, im sure they could be spun higher, though i know the power levels off at about 5k. the crank is.

all i was saying was that if anything was a limiting factor in how high one could redline, it would be the crank, not the cams.

i see what you're sayin though. there's no reason to redline higher if you're leveled off in your power band/curve.

-shaeff

 

[DEFIANT 7M]

DEFIANT: OK, so there's quite a difference between the supra and cressida intake cams, and I think it tends to be the valve timing on the intake side that has greatest affect on power curve location. (quoting my old engine rebuilding professor) Closing 14 degrees early should be very significant. Are the cam specs you gave a comparison of turbo vs NA, or supra vs cressida?

SHAEFF: I didn't mean the NA cam would enable you to rev sky high. Just that it would extend the power curve when you're up beyond redline.

Not much info, as far as I know supra vs cressida.

 

[DEFIANT 7M]

Here is the link.
http://forums.toymods.org.au/index.php?t=msg&goto=151543&rid=&S=94418905f5558a7b6c4472e57eb8098a