when you put a big cam in a car, for example, running a G5X3 cam with ls1 heads, what is meant by driveability issues?

 

When you go to a much bigger cam, in some cases you will have a rough idle. Depending on the cam you select you can also have a loss of lowend torque, making your car feel less powerful at low RPM. Both of these things can effect to way your car drives in daily traffic and how much you enjoy driving your car.

 

Just did this last week to my car. My car 2001 A4 Coupe. G5X3 on a 114 LSA. BIG CAM Idle is very lopey at idle, driving with my converter (SS 3600) has proven to be fine. Now the lopey sound and feel is only there at idle not while on the throttle. Honestly if I were to use my car daily I would go with something smaller as this is not fun in stop and go city traffic. On the other side the performance is AWESOME I ran 7 passes last night in the 11.6's at over 119 mph Cam, all bolt-ons, 3.73 gear and SS 3600 converter. STOCK UNTOUCHED FACTORY LS1 HEADS.

 

The term (IMHO) is how does it run with the air on, in traffic, and when below 1500 rpms.

I have the G5X3 and the car is driveable in all those situations, but you have to really that there will be times that it can have some issues. I have 4.10 gears so my time below 1500 is not that much, but in traffic I can see some surging. The surging is manageable, but if I was in traffic each day I would not like that.

With the air on the car takes an extra min. to adjust, but once it does the car is fine. Also it is a bit rough to start and needs some time to warm up, but again once it is warm the car runs smooth.

The tuning of the cam is just as important as the work to put it in so make sure if you are having it done you go to a place that has done yur setup a few times and knows how to tune it unless you are willing to be the test person.

 

I intentionally chose a smaller cam after seriously considering the G5X3 or something similar. I did not want to make my car any less fun to drive in the situations that I drive - trips, DC rush hour, around town. After looking at most of the cams out there and talking with the tuner I ended up with a 230-236 112 Comp EX-R. The car has a little lope - definitely not stock - and is drivable in all conditions. SD tuning made it work for me. Now I've got what feels like a stock car on steroids that even my wife could drive (thankfully no interest). I make 460-470 RWHP on a H/C engine with a ported LSX and LS2 TB and every bolt-on. You can have the best of all worlds.

 

Anybody know how the idle of the 114 vs the 112 is? I have been told the 112 makes a little more mid-range power, but the idle is worse...how much worse?

 

That very much depends on what you are willing to give up in order to get horsepower. When I first installed the G5X3 112 LSA cam on my 2003 Z06 it would not even start. I had to work on the PCM with HP Tuners. Even after a custom tune it is not at all like the stock setup. This particular cam loves high RPM ( I currently have my rev limiter set to 7400). The "lope" is a product of how long both the intake and exhaust valves are open at the same time(known as overlap) and the 112 LA is far worsethan the 114 (the stock Z06 cam is a 117 LSA).The reward for this difference however, is increased power for the lower LSA. With the stock cam you can 'lug' around town in 5th gear doing 30 MPH with no problem. With the G5X3 this is not possible. Any time the tach drops below 1500 in any gear the engine will buck and surge until the RPM's pick back up. With all this I still adore my G5X3 and I drive my car 100+ miles every day in and out of traffic. Once you get used to the cams' idiosyncrasies it will become 2nd nature for you and every time you step on the gas you will forget all about the driveability issues. Good luck with your choice!

 

I have the 112 and it is a noticable difference in "choppyness" at idle over my friends 114. I don't have to drive the car as a d/d so I love the muscle car idle and can deal with a little bit of surging. We had to bump the idle up to 1,000 RPM to take a little of the chop out of it, but it still shakes the antenna back and forth.

 

I went with the 112 lsa for more midrange power and torque, plus the added lope it makes at idle. When I do a drive thru at our local car show in the summer, I turn the a/c on and it really lopes like a much bigger cam...... When I park, people come over a want to know what's under the hood. Lots of fun!

Z06_Bob

 

Thanks for the responses! I think the 112 is for me. I'm all about road race events and want the mid range punch. As long as I can drive the car to and from events, I'm OK.

On another note, what about towing? I tow a small harboor freight tire trailer with Hoosiers. Will the cam effect my towing ability?

Thanks.

 

This is kinda an open question. Honestly, it depends on the tuning. With the proper tuning you should not see any difference in driving between a big cam and a small cam. There will be a difference in idle but thats more sound than anything else. I've been working on new tables for big cams and its taking alot of the driveability issues and throwing them out the window. My 346 is getting a 254/260 112 + 2, should have grown a pair and gone 254/260 108 + 0.
Phil

 

This particular cam loves high RPM ( I currently have my rev limiter set to 7400).


Damn! 7400

 

when an ice cream truck passes your car and you have to down shift to pass it...... its nice to post big HP numbers and Huge flow numbers for heads however if your not driving around wide open throttle your peformance suffers. I will give you an example.....while i am new to this forum i have owned many fast rides (back in 1991 i went 10.80@125 with a daily driver vortech-serial number 3 a trim mustang, 11.20's bolt on daily driver buick t type and most recently 9.0 @ 167 turbo hayabusa) lets look at the busa for a second my hp and torque were higher throughout the whole curve verses when i was normally aspirated. one would think that all things being equal i would walk a reasonably stock busa-pipe air box, custom map etc.... my buddy has 3 busas and we would ride all of the time, one day he shows up with a slightly modded suzuki gsxr1000 - pipe, airbox, map etc... we are running down the highway in 6th gear and he downshifts to second rolls on as i did and he was gone.... i mean he left me for dead....i was tacking 3k @ 75 my power did not kick in till 6500 and pulled like a ****** f*cker at 8-11k..... even when i downshifted into 3rd gear he was so far ahead that by the time my turbo spooled up the race was over.....now fast foward to a car example if you make power from 4500 to 7k based on the cam specs 228-234 and higher this is your power band... your not using 20% of your cams power band since your car is done by 6500 rpm....(i am not certain the stock c5 peak rpm and maybe someone could correct me if i am wrong) you would be better with a cam that had a power range from 2500-6500 like one with a 218-226 duration. look at lingenfelters cams.... i know he does not have the fastest cars on the planet any longer but his cams (comp) dont have a lope...they sould like a stocker pass emissions and beat 99% of any street cars..... my .02 cents

 

I think this depends on the driver.

What I beleive it comes down to though, is that a "cammed" out car will not reward a lazy driver. This is one who like to punch the gas in any gear and go, or one who can't downshift and heel to toe at a moments notice to keep momemtum up through a series of corners. It's easy to leave the car in 4th and torque your way through everything.

But, I think a highly skilled driver will be faster in a "cammed" out car, because he is constantly paying attention to what gear he is in and how the power band reacts. This will reward the skilled driver. The experienced driver is already in the right gear and is heel and toe'ing at a moments notice.

I think you need a cam that suits your driving style. If you are a lazy driver that likes to pull in any gear, then you really want a mid range cam, if you are a driver that is extremely attentive and ready to work very hard to be fast, you will be faster in a bigger cam. What about the guys that drive Honda S2000's? They would laught at us, as their power doesn't come on until 7k+. I think even a "cammed" out Z06 will still have more torque down bottom than your typical small displacement (even with turbo).

 

When you change a cam it is giving you high end power and moves the power band high up. Putting in a medium size cam does this effect less. If towing and low rpm performance is your goal start with 4.10 gears and if you still want high end power get the g5x3.

Any cam that gives you that kind of power up top moves the power band up and takes away from low end poower. That is why gears are even more important for a hugh cam.

It sounds to me like you need a gear change and not a cam change.

No cam change will give you the pull effect like 4.10 gears will.

 

In all honesty, I think 4:10 gears are way too much for a road course. I'll be in 4th gear by the time I hit 100, and no matter what rear you have, 5th is a gear is an abosulte waste. This is not what I am personally looking for. I do think for drag/street racing 4:10 gears are perfect. I have previously owned a Mustang with 4:10 gears and 450hp and know exactly what the effect is...Lots of off the line power down low with very little top end. My mustang would pull like hell up to 130 and then fall flat. I need something that will pull from 120-170mph. I rarely fall below 60-70mph, so that off the line power is not important. Also, I have a Z06, so my tranny is geared differently. A Z06's gearing is similiar to having 3:90's on a regular C5.

I can see how you would recommend gears, but no offense, the gearing is perfect stock. I am always above 3300 on a road course and are sick of the car running out of steam at 5k. The cam will solve this problem. It's different when your already doing 100+mph on the back stretch of Watkins Glen and a Porshche turbo begins pulling on you after 130. The higher RPM power will help me keep my speed up on a road course vs 0-120 type power that 4:10's give you.

 

...not a type-o; my rev nanny is currently set @ 7400. And on the few occasions when I have bounced off it the G5X3 was still pulling hard. Thank the powers that be for Comp 921 springs!!

 

my question to you, is where do you think the cam starts making power? 3k 3300, 3500, 3800?

 

Sat is a car with a G5X3 last night...totally driveable on the street. No problems at all. The problems in my opinion were all a myth

 

Myth? Surely you're not going to make a judgement call after one experience. I'd say that car had an excellent tune.

I can vouch for Electra's post since I've ridden in his car and I also had the same issue on a previous car initially with a large cam ('02 WS6). I am all for the G5X3 (which I'll probably put on my '03 Z06 very soon) but you'll see what people are saying when you get one.