I have been debating on a cam upgrade...like most on the board, and am now confused on whether a XER lobe is necessary on the exhaust. I am pretty certain I want to go with a 228/.588 XER on the intake, but am thinking that an XER lobe w/ a 234/.598 on the exhaust is over kill...and is a higher lift than I want to go. The "Extreme RPM" lobe puts the lift at .571 w/ the 234 exhaust duration, which is a "safer" lift w/ my 987 springs. My current setup is TEA SII 5.3 heads milled .015 w/ the TR224/.563/114. I will also tighten the lsa to 112 (+4).
Any input here is much appreciated.
Thanks.

 

Mark talked me into a 230/238, from what I read it'll be just what I want. I should know for sure next weekend.
What do you want it to do that isn't getting done now?

 

Hey Bob, glad to here you are getting it back...that should be a freakin beast!!!

to answer your question....HORSEPOWER...just trying to squeeze that last bit out of the stock cubes.

Back to my original question....I will simplify this time. Is there much to gain from a XER lobe vs. a XE lobe on a high exhaust duration cam?

 

No, there's such a little difference between the .59X and .57X lift. Although if you have Dual Springs I really wouldn't worry about it.

With that cam you're going to need a steep gear to get in the powerband and slicks to not sping yourself like crazy out of the hole.

 

Scratch that, I noticed that you said you were going to bottle it, you'll run really damn good on the bottle but I'd stick with the 114 lsa and 57X lift. You'll still need a bit of gear to run good, but your all motor times won't be the greatest.

Just my $.02 take it for what it's worth.

 

Why do you say the motor runs won't be the greatest with that particular cam and gears, say 3.73s?

 

Well I didn't see the 3.73's, listed in his sig so I assumed 3.42's. 3.73's wouldn't be a tall enough gear matched to that size of cam to run the best it could on motor IMHO, but he's building it for N20 and a 3.73 or 4.10 would work very well. Again this is just my Humble opinion.

 

BLUBYU has 4.10 gears already.

 

Well then he's set, just trying to say get in the powerband or he'd get dissapointed.

 

Thanks for the input.....but still need an opinion on whether the exhaust side benefits with an XER lobe if you have a high duration? Is there much to be gained going from a XE to a XER lobe?
Thanks man.
Btw, I am trying to build a good compromise for NA and nitrous.

 

I researched the XE vs XER lobes when I was choosing camshafts. From what I've gathered There isn't going to be a huge difference but in theroy there should be some gain going with the XER. How much? I'm not sure.

By the way sounds like you got a pretty bad assed setup there man, mark definetly helps make a lot of people's go faster.

 

Well if it were me I'd stay with the XE lobes. They will be easier on your springs and run quieter, plus I doubt you would notice the difference in power.

 

Just got back from the weekend....thanks for the input. I am thinking the same thing. I am going to call Jason @ TR and see if he has finished his R&D w/ the "big" cams. He most likely though is using XER across the board though.
Later.

 

I would go with a reverse split. Use the XE-R lobe on the intake side and an XE high lift on the exhaust with the same overall duration. For example, I am running a 220/220 .581/.566 cam. It looks loke a single pattern but it has 5 dgrees more duration at .200 and .300 lift. It has a great idle at 700 rpms and it pulls like a bat out of hell. Read up on reverse splits. They are the only way to go.