cams cams cams

[Alex170984]

harkes Wrote:Hi

As mentioned you dont need nearly as aggressive cams to make ~140 crank-hp (must be since your std setup delivers 127).
My previous engine made 150hp with 256 Cat-cams and my current make 189 with 290 Kent-cams. Measured on the same dyno

That's good to hear - i've just fitted those 256 cat cams - and looking for that output

Wait no, they are 252/260

[oldeskewltoy]

NoHachi Wrote:Wheel-hp will vary as much as 20% between dyno's and is as useless as engine hp. Sometimes more (see e.g. Mahle dyno's or dynojet dynopac)

just a random brain journey......

My car has now been on 3 different dynos... the readings have been 140 whp, 145 whp, and 142 whp... respectively

There have been no mechanical changes to the engine, the only changes have been in the engines tune.... and most WOT runs are easy enough to replicate.

My engine: Web cams 577 (264 type) TRD springs, light weight wrist pins - all other internal parts are stock... with carefully targetted machine work and porting.

I know I've been rambling... but my point here is I'm not so sure dynos are 20% different.... I believe it to be other variables like operator error - this is big because it means all the prep too - like tire pressures, and correct fitment to the dyno. Case in point... My All-Trac Corolla planted 40% more power with 28psi, as opposed to 23 psi in the front tires alone

[Apsogos]

on my ae92 gti corolla with 195 50 15 tyres i am usings 32 psi in front and 30psi on the back

[jondee86]

This is one of the reasons...



And this quite likely is another...



And for some interesting reading, the main article here...
http://www.popularhotrodding.com/tech/11...ine_dynos/[/img]

Cheers... jondee86

[Apsogos]

i want to make an objervation. When i ve bought my rolla ae92 some years ago it was with 205/40/17 wheels , the car did not perform well...
When i bought the 15'' inch wheels it was another car! i couldnt install 14'' cause i have the twin brakes of levin

[jondee86]

Apsogos Wrote:When i ve bought my rolla ae92 some years ago it was with 205/40/17
wheels , the car did not perform well...

Exactly... big wheels make your car slow. Why ? Because putting big
wheels on is like changing your diff ratio to a lower number. On an AE86
with a 4.3 factory ratio, changing from 15" to 17" would be like installing
a 3.9 ratio... good for autobahn cruising, but bad for acceleration.

Cheers... jondee86

[Apsogos]

do you believe that 15'' wheels are decent size?

[Ivan141]

For best performance, bigger wheels seem to be the better choice (assuming relatively equal rolling diameter with tire).
For practicality, 15" wheels are king.
-Plenty used & new for sale.
-Enough room for wide tires & big brakes on an AE86.
-Cheapest tyre selection (195/50/15 is the cheapest size there is at the moment).

[Apsogos]

Ivan141 Wrote:For best performance, bigger wheels seem to be the better choice (assuming relatively equal rolling diameter with tire).
For practicality, 15" wheels are king.
-Plenty used & new for sale.
-Enough room for wide tires & big brakes on an AE86.
-Cheapest tyre selection (195/50/15 is the cheapest size there is at the moment).

[Bean]

megabob go with superli's advice (you'll benefit more from extra lift than overly high duration). Everybody else: 1st he asked about cams and not dynos. 2nd as he clearly stated two figures it's simple to see he's looking for around an extra 10%
This is achievable with cams and what he has.

PS: sorry for the "rantish" post but getting really pissed about all the dyno discussions.