yes with the same boost and no other changes the car would gain about 50whp and about 60ftlbs tq. u could lower the boost a few psi and still make 500whp. that is only if u have enough fuel and ur motor can handle the extra power.

 

Are you sure or you think it will on a set-up allready maxed out?

We all saw the gain on the graph from 3SX with no other addition, I just need to be confirmed it can be done on set-up allready maxed, if a car get some knock with an airflow of 61lbs/min, how can it make an airflow of 65lbs/min without knock by adding some cam gears!?

Eric

 

I think it has something to do with the area under the lift curve using the +1 intake cam setting thus resulting in a more optimized airflow because the valve stays open longer. Even if you are maxed out on a setup I would think you could still gain hp from cam gears because all you're doing is modifying the time the intake and exhaust valves are open. The airflow is already there you're just optimizing it.

 

Could make sense. I still wonder.

For daily driving, does it affect the idle ? more choppy ?

Eric

 

Cam gears shouldn't affect the idle. Big cams will like 280s would give you a noticeable lope. 272s might give a little lope.

 

if your not limited by your fuel (i.e. you are running maximum boost your turbos can sustain) then the gears will probably not help much. The turbos can only flow so much.

Now, if you move to a different area on the turbo map to where the turbos are more efficient you may make more power, but I think in general if the turbos are maxed out the gains will be very small.

Now, on low octane fuel the gains will be greater because the turbos aren't out of breath.

 

Thanks guys.

So technically you think we we are able to push more air (if the turbo allows it) before the knock start !?

I understand the principle of the cam gears, we augment the overlap with the +1, -3.

+1 on intake = intake's valves are opening sooner.

-3 on exhaust = exhaust's valves exhaust closer later.

A bigger overlap means that the intake & exhaust valves will stay open longer and will allow a better aspiration of the air going in by the inertia of the exhaust gaz going out. But I still don't understand why a car get some knock with an airflow of XX and could run an airflow of XX+10% without knock by adding some cam gears with the same fuel!?

Because more air in the head, means more compressed air, compression means hotter combustion, means knock, normally.

I'm just trying to understand, I may be completly lost and shoving clouds...

Eric

 

I would still think you would see some gains from cam gears even if the turbos have reach max airflow. When that happens the turbos haven't completely stopped pushing air. When the valves open sooner you'll still be getting more air in the cylinder compared to not having adjustable cam gears. I don't know how much of a gain it would be but surely it has to amount to something even if it's smaller than the gain at a lower psi.

 

Note on the side: I just printed the 2 graph from 3SX, we cannot overlap them cause they are not the same size exactly, but I did it manually, I was wondering if we were loosing power somewhere on the chart, and... nope, not at all, the curves are the same under 4500rpm, but then after the aftermarket cam gears (+1,-3) shows gain all over from 4500 up to the end (7xxxrpm)! So it keep all of the downlow torque, pretty nice!

Eric

 

My understanding is advancing the intake timing will help spool the turbos faster by pushing more air through earlier, but will cause the turbos to taper out a bit earlier as they "run out of breath" so to speak.

Retarding intake timing will cause it to spool a bit slower, but to hold the powerband better and with less taper.

So, from what I know, the cam gears mostly let you shift your powerband left or right a bit. They CAN make more power overall, but the car would probably need the timing map adjusted too. I'm not sure they'd increase the peak horsepower once the car is at it's limits, but they could certainly help make better use of the potential power, which, even though it isn't higher numbers, is a faster car.

 

Is it just becuse you`re knock limited to 20psi?.

I`d suggest chucking more methanol in there, at 2l/min pure meth I can use anything my turbos can dish out knock free..

 

I'm just looking what parts would be good to add with the DR750's when the engine will be out of the bay, to do all at once. I plan to tune the car for the max on pump + water/meth, and was wondering if cam gears would net me more WHP/TQ under the curve, aka raise the limit or only move 'the curve' to the right.

Eric

 

Those DR 750`s look nice, wouldn`t mind a set myself!.

 

I was wondering about the gains on the 3sx cam gears also. Im doing a build next year and wondered if i should get them. I mean from the dyno charts you cant beat adding 50whp and 60tq to a 500whp car for $285.

 

From a different thread:

Now this is the way i understand it, if i am wrong someone please feel free to correct me.Valve overlap is the amount of time both the intake and exhuast valves are open at the same time. By increasing valve overlap, you can create a better suction effect on the intake side. Instead of the exhaust side just opening with the intake side closed creating little to no vacuum, you can have the intake side open and the exhaust side will actually help to suck air through the intake valve, creating a better efficiency. By doing so you create better upper rpm power, but lose some lower rpm power. Like IPO said, it doesn't affect the timing of the engine, just solely the valves.

So by doing this it sounds like you are getting a little more fresh air into the combustion chamber than you would under stock conditions, making a lil more power.

By getting cooler fresh air into the combustion chamber, id guess you get a more even burn (assuming there are some spent exhaust gases in there normally) and less hot spots in the chamber reducing the chance for knock. Just a guess...