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I am looking to invest in COMP Cams grind number XE274H and can't find much on it here. Will this work with NPI heads, so long as the springs are upgraded?
 

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I would get a milder cam. You will have a substanial loss of vacuum and a very lumpy idle with these cams. It is also nessary to get the valve springs with any comp cam. I would get the xe262h if you want to have power brakes.
 

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Get the 268 grind NPI cams and the valve springs, the springs will give you a sense of confidence ,and the duration/ overlap on that grind gives nice power... the Idle will be mean enough, there will be no vacuum or driveability issues, and the torq loss at the bottom end will not be as bad... comp techs say that the higher lift cams for PI heads require head mods to run on NPI heads .... good luck....
 

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Name: XE274H
Number: 102300
Lift: In. .500" Ex. .500"
Duration @ .050": In. 236° Ex. 240°
RPM Range: 2000-6000
LSA: 114º
Description: Hot street/3.55-3.73 gears/2000+ stall/Upgrade EEC/rough idle

This one doesn't require the retainer to guide clearance modifications.
 

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get the 268 thats what i have in my 95 heads just use comp springs and 96 tbird retainers and it will go and all i can say is the cams make nice top end i just run out of air on the stock heads but the cams make power along time
went a 13.85 with the stock intake lol
 

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Last I heard thats the cams that JL is going to put in his new motor... good enuff for him? 'nuff said......
 

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I know of members of this board running cams with that much overlap and have had no problems with their brakes. That being said, I think anything larger than this would have problems. The fitment problems have been mostly with the xe270ah and xe278ah grinds. I don't think these will be a problem due to the lower lift, but be sure to rotate the engine a few times once they're in to double check.
 

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I ran the XE268H cams in my car with a lower custom ground LSA with MORE overlap, and had no vacuum issues. Lumpy idle, yes extremely... vacuum issue, no...

When I started my SC build, I sold em off to a guy who's running them in a high compression N/A set up.. He's not having any vacuum problems either. I haven't heard anyone complain about vacuum problems with any of the compcams, but there have been some PTV issues with the XE270H's (PI heads) from guys that have not degreed their cams when they installed them. There is a 5* advance ground in them that has to be considerd when installing them. Best thing to do is have them ground without the 5* advance.

In NPI heads the only grinds you can use without modifying the heads are the XE262H, XE268H & XE274H grinds. The 262 are too low-endy (towing, etc), and the 274's are too high-endy for most applications .. the 268's are fine. I highly recommend upgrading your springs to Compcams springs.

-mike
 

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mylittleblackbird said:
Leland, what grind is JL putting in his new motor?
XE268H - 102200 grinds

I know this for a fact...

-mike
 

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A PI Cam vs. a XE268H what kind of HP differences are we looking at?
I'm running PI heads...see below.
Is it worth 500+ bucks to do this?
The reason I ask is I'm looking at future mods.
Thanks.
 

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mylittleblackbird said:
I just wanted to verify. Lots of grind numbers were getting thrown around and I wanted to be on the same page.
I understand, it wasn't real clear... Before I bought my cams, I spent a lot of time talking which ones over with JL.. He had done a ton of research on what was available. He had talked to John at Modular Performance (who is doing amazing things with the modular engine) and Dennis Miles at Compcams, as well as Jim at Renegade (who was putting Compcams in his heads), Jerry W. and lots of others. the 102200 seemed to be the best all-around choice that was out there, for the NPI heads.

At the time my goal was to get to 300rwhp and 12's N/A, so I had them custom ground with a longer overlap LSA. I was at 223rwhp with the PI cams and an aggressive SCT tune. With the Comps I got to 245rwhp (with the corked stock NPI intake), but the tune was kept very conservative because I was adding an SVO intake, and my bottom end was at risk (over 300 crank hp). I'm sure with an aggressive tune, I'da been well over 250rwhp with the stock intake. I figure the cams are worth close to 30 hp.

Initially with the PI cam tune, the Comps caused some driveability issues. Idle was very lumpy, but didn't stall out.. actually the car would pull in gear at idle with a 3200 stall converter. However when I gave it a little gas to move small distances, like in and out of parking places, and in the staging line at the track, the car engine would want to stall... That was due to the overlap LSA.. off-the-shelf 114* grinds don't have that issue. SCT was able to cure the driveability issues with a tune. The SCT Guys drove it around Atlanta during the tune weekend and tweaked it as they drove it...

-mike
 

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17Mark71 said:
A PI Cam vs. a XE268H what kind of HP differences are we looking at?
I'm running PI heads...see below.
Is it worth 500+ bucks to do this?
The reason I ask is I'm looking at future mods.
Thanks.
I don't know what the cams would be worth in a unported PI head application. Like anything else, it's the total combination that determines the final outcome...

From what I am hearing 25-30 hp gains in NPI heads is what everyone is getting over the PI cams in NPI heads... Hans Solo just pulled 281rwhp with those cams on Renegade NPI's and a PI intake... Since JL was around 250 or so with Renegade NPI's, PI intake and PI cams.. that sounds about right...

Comp makes grinds specifically for PI heads. The XE270AH is the equivalant of the NPI 268, but there have been some PTV clearance issues due to the 5* advance Comp grinds into those cams... You can order them custom ground without the 5* advance.. that's probably the way to go...

The man to talk to about cams is JL, or John at Modular Performance. John has sold a bunch of the Comps and can tell you what is working in what the best. He also has other options he can offer.

But yes, I would say that the Comps are way worth the investment. Look at what what folks pay for underdrive pullies, aftermarket plenums, and TB's to get single digit gains. $500 for 25hp is a bargain... IMHO

-mike
 

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96GB: Thanks for the advice. I'll check with John and JL when I'm ready to do this.
 

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17Mark71 said:
A PI Cam vs. a XE268H what kind of HP differences are we looking at?
I'm running PI heads...see below.
Is it worth 500+ bucks to do this?
The reason I ask is I'm looking at future mods.
Thanks.
If you've got the last isue of MM&FF,they have a cam thrashing test in there.
the Comp 268H's vs the PI's.. the 268H picked up 37 hp at the peak,and 53 hp at 6500 rpms,while picking up 10 ft-lbs peak,and 47 ft-lbs at 6500 rpms.
They work well,and are a nice safe grind for long life-they don't stress the valvesprings as much as the higher lift cams do.
I've already heard of a couple of sets of Comp Springs broken...But they're at least fessing up,and have pulled them all until they get a new batch of materials in.
JL
 

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So I assume that I can run the 268's or even 270's in my PI heads even though they are designed for NPI heads. They're just lower lift (.500 vs .550) which makes it a little safer from possible PTV contact. Am I trackin' right here? Thanks again.
 
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