Forum » Off Topic Discussion » Camshafts!

Camshafts!

Off Topic Discussion

If it's not really about tuning or wiring. Then it belongs in here.


Page 1
Author
47 Views

Hi ive got a question, it may not make complete sense but ill try my best to explain what I am thinking about... but basically will larger camshafts increase top end MPH drag racing purely because of the Torque increase and not because of the HP changes on a dyno...

so I have a Stock standard set of camshafts in my Toyota 5EFE 1500cc engine... it makes 301WHP on 21 PSI of boost right now... lets say peak torque is at 5000rpm... and drops off after 6000 rpm, even though the engine HP is still climbing at 7000 RPM when it hits the limiter...

***now for the test***

If i go and increase the camshafts size, We would then adjust the AFR/lambda to be the desired amount, we then lower the boost pressure to try to target the same peak HP as the standard cams... So my question is, even though the HP outcome is almost the same in both examples, will the extra torque in that upper range with the larger cams result in a Higher MPH/top speed, in my case a drag racing application? OR would it remain the same?

My twin engine Starlet currently runs 110 MPH half track and only gaining 23MPH in the last half of the track? It really feels like it lays over after half track... Its got me stumped what it is... But then I have watched some of the ALL motor civics running into the 9s in a full trim street car, which has lead me to believe that their enormous camshafts are putting the engine peak torque right up into the top of the rev range where it gets used efficiently? Also ill factor in that the Turbos I am using (one on each engine) they are a GTX 2867 with a .72 rear housing.

sorry for the life story I hope ive covered all bases...

Attached Files

To answer a question like that you either need the torque/power curves and gear shift points...or some data logging.

Where is the other engine? (You said twin engine??)

Sounds like you might need some different gear ratios... You should play with one of the simulation programs that takes the torque/hp curves and let's you modify the gear ratios.

One in the front and one in the back lol two of everything. Sounds complicated but its really not...

https://www.youtube.com/watch?v=5eXcJ9-StNs