Whats the quickest 1/4 mile time for a manual TT Zed running standard Cams and diff gears, also maximum rwkw for a motor with standard Cams. Eddie
I think about 600rwhp and a high 10sec pass. Its a shitlaod of work to get it there, dont think its easy.
Interesting; then why do people go for larger cams, I was thinking about replacing my with larger HI-left units, but if the standard cams can manage 600hp why waste the money changing them. Thanks Eddie
My understanding is whilst cams will slightly delay power production, higher peak power is achieved with lower boost, this makes for a safer high power engine. And it sounds hot. I think 600 HP on stock cams would require boost in the high 20's, and PULP fuel octane is out of range for detonation resistance, starts getting a bit hairy for reliability.
It all depends what you are after from you engine A few facts. The torque curve is what determines you engine's characteristic. Power = torque X engine RPM. A good rule of thumb is for cam shaft selection, you can change the area under the torque curve with a cam profile change, only its shape. Therefore you can select where the torque is delivered. So it is not just a case of bigger and longer duration is better, as you need that velocity of the air to be entering the camber. There is a lot of work behind this, and though as you potentially can cause grief (make you car undrivable on the road) by just swapping cams. At the track I suggest that you are looking for an extended torque curve to the top end of the rpm range. On the road for a daily, a torque curve that develops very early and linearly. For the drag strip, maximising the torque avaliabe in the RPM range of gear changes, and for a dyno queen you need the torque only for the last fewRPMs. I wish people would get away from setting thems self peak RPM targets, you really should be looking for an appropriate torque curve for you intended purpose. In addition a wild cam can work with a correctly sized turbo to give a good curve. i.e have a turbo that spools from 1500 to fill the torque curve until the cam works in the high RPMs. Makes sense? To give you an idea of matching cams and purposes. I have the auto cams in my blue e-vade. As it is meant for the road and my wife like to drive, it can happily pull its self form 1200rpm. Which, is a bonus as she is in top gear before you hit 50km/hr normally I fill my area of the torque curve using the EBC map of the ECU to bring the boost on in two stages; boost target 1000-4500 6psi, 4500-7000 12psi. Where the track car is all about the 5000RPM plus range. I hope this makes sense and helps you make the right decision. As I am trying to show that all engine mods, (actually all mods) need to be consider in conjuction not just isolate them.
this was awesome, I am looking at drag and once I get up I stay above 5000rpm. with better tyres I could TBrake to 4000rpm and nitrous at 4200 so It would be at 5 very quick. what kind of cam would you suggest for such a setup. I will be running sky high boost and e85 with a 100 shot on top.
Good post. Just to expand or rather spell out in more detail (sorry I'm a physics nerd)...your car's acceleration (a) is given by Newtons 2nd law of motion i.e. a=F/m For your car F is the Tractive Effort (TE) at the rear wheels (assuming its real wheel drive). That is car acceleration = TE/car mass The TE at the rear wheels is proportional to the torque T at the rear wheels . In particular T = TE*r where r is the diameter of your wheels (assuming no energy lost in the wheels albeit in the real world there will be). That is torque equals force times distance where in this case the force is the cars TE and the distance is the wheel diameter. Or rearranging TE = T/r Rear wheel torque will of course be proportional to your engine torque (but less due to energy loss in drive train) and is of course also a function of what gear you are in, what your gear ratios are. So basically your cars acceleration at any particular rpm is proportional to your engine torque at that rpm. So basically you want high torque everywhere as for a given gear your average acceleration from low to high rpm will be proportional to the area under the curve of the torque versus rpm graph. If you shift your torque from low rpm to high rpm but do not change the area under the torque vs rpm curve your average acceleration over the whole rev range for a given gear will not change. However because horse power is proportional to torque times rpm your maximum hp reading will go up and you might win a dyno competition but you won't actual increase your over all acceleration from low rpm to high rpm, you've just shifted where you do your best accelerating from lower rpm to higher rpm. On the race track where you're presumably always in the lowest gear possible (to get the best acceleration) you will appreciate having your torque at higher rpm (where your engine is spending most of its time). But on the road where you're going to look like a d*ck if you're constantly screaming round at high rpm in everyday traffic you will benefit from more torque lower down in the rev range (where your engine spends most if its time). I've read before and dieseldave confirms it that changing your cams does not change the area under the torque curve (much if at all) it just changes where your peak torque occurs. So changing your cams to give more torque at high rpm will give you a better max hp result (dyno queen) but may actually make your car slower at everyday road driving rpm.
