XR288HR vs XR274R help decide, or give me a better option [Archive] - Team Camaro Tech

: XR288HR vs XR274R help decide, or give me a better option


Spames
Jan 13th, 10, 11:29 AM
Rather than hi-jacking the solid roller thread ;)

First, I'm inclined to have either of these ground on 108LSA/104ICL...

Secondly, assuming the XR274R is indeed a better power maker, how much are we talking, and how is it achieved?

hydro-roller XR288HR (with 1.6 rockers?)
http://www.compcams.com/Cam_Specs/CamDetails.aspx?csid=161&sb=0

VS
solid roller XR274R (with 1.5 rockers?)
http://www.compcams.com/Cam_Specs/CamDetails.aspx?csid=305&sb=0

I'm trying to stay close to .600 lift with the good flow characteristics of the AFR's
Max RPM 6000-6500

Going in a 383 11:1 compression, AFR 195 eliminators
Performer RPM intake
800CFM qjet
Manual brakes (vacuum not a concern)
Super T-10 4 speed trans, 3:73 rear 26" tires

Feel free to make another recommendation if you don't like either of these.
Thanks

JayBird
Jan 13th, 10, 12:17 PM
I have had a hyd roller and switched over to a solid roller (XR280R) and like it alot better. I have 1.6 rocker on intake and 1.5 on exhaust. I think you will be happier with solid roller vs hydraulic. I think your combo could handle the 280XR very easily.

zdld17
Jan 13th, 10, 12:44 PM
The rpm you are trying to maintain, tells me to stick with the solid 274 roller as I had the 288 comp hydra roller and it being a hydraulic, limits some rpm , especially if you have no rev kit.

I would also suggest you maintain high spring pressures with either cam to control lifters on the opening and closing ramps of the Comp cam if its a billet. I would not recommend high spring pressures over 140# on the "austratempered " comp core. Its basically a cast core. I had this cast version and had problems with flakes of cast coming off the opening ramp as well as fuel pump eccentric lobe wear.

Since going to one of UdHarolds billet grinds, I have had no issues.

Spames
Jan 13th, 10, 01:06 PM
Since going to one of UdHarolds billet grinds, I have had no issues.

What grind did you go with to replace the 288HR? I'll be running an electric fuel pump with a late model 4 bolt vortec block, so no fuel pump issues, but I'll watch out for the high rates on the regular comp cores. Thanks

Spames
Jan 13th, 10, 01:14 PM
I have had a hyd roller and switched over to a solid roller (XR280R) and like it alot better. I have 1.6 rocker on intake and 1.5 on exhaust. I think you will be happier with solid roller vs hydraulic. I think your combo could handle the 280XR very easily.

I was trying to keep torque up on the low side as well. This sled weighs about 4050 with me in it. -- Wouldn't something with more duration move the power curve up a good bit?

Greg O
Jan 13th, 10, 02:33 PM
Spames, It is really a personal preference...I happen to prefer the "no worries" aspects of the hydraulic cam and have been very happy with my XE294HR.

I would venture a guess that the performance between the two would be nearly identical. You could probably get more RPM out of the solid but HP would be within 10 of each other.

JayBird
Jan 13th, 10, 02:51 PM
I was trying to keep torque up on the low side as well. This sled weighs about 4050 with me in it. -- Wouldn't something with more duration move the power curve up a good bit?

My car doesnt weight 4000lbs, but with a 383, good heads as you have, I really dont think torque is gonna be a problem. I suspect you will make 400-425 tq around 3200-3400rpm and make 500lbs by 4500rpm. I think you like like the HP and torque curve that a solid roller makes and still turn more rpms. Its your decision as its your $$$.

Spames
Jan 13th, 10, 03:59 PM
I'm thinking it would cost about $400 extra to do a solid roller over hydraulic.

Ls7 lifters + 288hr = $400

solid link-bar style lifters + solid roller cam = $800

I'm trying to figgure out if it's worth it for a 6000-6500 rpm 383.

sik68
Jan 14th, 10, 12:29 AM
Hey spames. For what it's worth here is my 355 with the xr274r idling and blipping a bit. It. Idles down to 800 rpm but gets a little rough there. I don't run power brakes so I can't comment on that. I just drove the car once on a shakedown run so I can't give you too many impressions on power. With the manual trans, the car does buck under easy acceleration at less than 1800rpm. I wanted the 280r but my engine builder predicted correctly that the car would buck, and that I needed a bit more displacement to go with the 280r. Those 2 cams run the same springs I believe, so it was really a toss up. I spoke with comp cams who said the power difference between the 2 is small in a 355l, and that lashing the 274 tight will get you half way to the Duration specs of the 280. Just watch piston to valve clearance. It's not a gimme with a solid roller.

Hope that helps! Feel free to ask more questions
YouTube- Broadcast Yourself.

Your planned combo is pretty similar to what I have. 355, 200cc pro topline heads with mild work, port matched air gap with a 1" spacer, pro systems double pumper. I hope to be on a dyno next month so stay tuned!

Spames
Jan 14th, 10, 06:26 AM
Sounds nice - seems very responsive!

zdld17
Jan 14th, 10, 08:38 AM
What grind did you go with to replace the 288HR? I'll be running an electric fuel pump with a late model 4 bolt vortec block, so no fuel pump issues, but I'll watch out for the high rates on the regular comp cores. Thanks

UDH CCC 282/290 with 112 LSA. Idles like a stocker but flys well with the new Eliminator AFR 195 heads, I am using retro rollers but if you can find a late model block , you can use the stock rollers and spring dog bones. Local chassis dyno recorded max hp 375 rwhp @ 6130 rpm. Tq was about 355 max @ about 5k, Power seems to fall off after 6100, but its a street car and hyd rollers ..

Spames
Jan 14th, 10, 09:20 AM
UDH CCC 282/290 with 112 LSA. Idles like a stocker but flys well with the new Eliminator AFR 195 heads, I am using retro rollers but if you can find a late model block , you can use the stock rollers and spring dog bones. Local chassis dyno recorded max hp 375 rwhp @ 6130 rpm. Tq was about 355 max @ about 5k, Power seems to fall off after 6100, but its a street car and hyd rollers ..

Nice!

I have a like new GMPP 880 4 bolt block with all the factory hydraulic lifter retainers already.

I also just got the latest (2009 edition) "How to build max performance chevy small blocks on a budget" by D.Vizard - I'm planning on studying that book pretty hard. Hopefully I learn something :D

dylanjans
Jan 14th, 10, 10:01 PM
Hey spames. For what it's worth here is my 355 with the xr274r

Hope that helps! Feel free to ask more questions
YouTube- Broadcast Yourself. (http://www.youtube.com/watch?v=YfnbwkMvm-g)




I watched your first drive. Looks like it is going to be a fun car!
Good to see someone having some fun. It makes up for all those days you want to throw a wrench at a car.

BPOS
Jan 14th, 10, 11:10 PM
There's an XR282HR in between those, essentially what I have in a 9.5:1 383. Runs hard.

Edit - Nevermind - noticed the 274 is an SR.

BPOS
Jan 14th, 10, 11:12 PM
UDH CCC 282/290 with 112 LSA. Idles like a stocker but flys well with the new Eliminator AFR 195 heads, I am using retro rollers but if you can find a late model block , you can use the stock rollers and spring dog bones. Local chassis dyno recorded max hp 375 rwhp @ 6130 rpm. Tq was about 355 max @ about 5k, Power seems to fall off after 6100, but its a street car and hyd rollers ..

Don - are you making those RWHP numbers in a 306? Impressive!

Spames
Jan 15th, 10, 06:56 AM
I did some light reading, and in looking at a DV cam, I found the following recommendations:

"Fast Street"
Min. Cr: 9:1
4deg. advance
in/exh duraton @ .050
231/231
He recommends 1.65 rockers with a 383
for lift of .589/.589

Similarly:
"Max Street"
Min CR 9.8:1
239/239 @.050
Lift with 1.65 for a 383:
.605/.605

And also:
"Street Strip"
Min CR: 10.5:1
243/243 @.050
1.65 rockers
lift .615/.615

I can't make up my mind
I wish it gave RPM ranges in his charts, it would make narrowing down his recommendations easier.

zdld17
Jan 15th, 10, 07:47 AM
Don - are you making those RWHP numbers in a 306? Impressive!

No longer a 306 internal motor,, I still have the 302 CE block but with 383 crank. All in all, I am not too impressed with this set up when compared to my older 355 with the same stuff. I still feel the 355 would blow the 383 away, in its present form. I built this for cruising, now if strip was on my mind, things may be different.
Maybe I am asking too much from this set up considering what it was built for.

As for your cam selection, if this is 90% strip, I would go with 243/243 if you have good eliminator heads .

Spames
Jan 15th, 10, 08:18 AM
No longer a 306 internal motor,, I still have the 302 CE block but with 383 crank. All in all, I am not too impressed with this set up when compared to my older 355 with the same stuff. I still feel the 355 would blow the 383 away, in its present form. I built this for cruising, now if strip was on my mind, things may be different.
Maybe I am asking too much from this set up considering what it was built for.

As for your cam selection, if this is 90% strip, I would go with 243/243 if you have good eliminator heads .

It's more like fair weather toy driver when I'm not carting kids or family around. I want decent low end power and no bucking under 2000 RPM. Strip isn't the most important, but I do go to the track 2-3 times per year. It's not a strip machine, but it's not a daily driver either.

And I'm definitely sold on the 195 eliminators for this project.

zdld17
Jan 15th, 10, 08:34 AM
It's more like fair weather toy driver when I'm not carting kids or family around. I want decent low end power and no bucking under 2000 RPM. Strip isn't the most important, but I do go to the track 2-3 times per year. It's not a strip machine, but it's not a daily driver either.

And I'm definitely sold on the 195 eliminators for this project.

Well if you want no bucking, you can compromise, you need a deep gear, 3.73 or 4.10 to run the 243 cam , IMO or go to smaller one to accomodate what ever gear you have.. I have the 282/290, thats 231/239 duration with 112 LSA, I run 3.73 gear but I also have a TKO. Gets 23 mpg out on road and I can go around a corner in 4th with no issues. No lug/buck providing I dont lay on it hard, once rpm gets above 1500, it pulls hard.
When I was in the market for a cam , I had a hard time making up my mind between the cam just below the 282 which was the 274 which was a 110 Lsa cam. Then after much good words on Ud Harolds cams designs, I call them, he recommended his version of the comp cam but with 112 Lsa, I told him the car was a cruiser car with AC added. This was the reason he recommended the 112 lsa cam. Otherwise, I would have gone with the comp 274, I liked the rpm/power graphs but the 294 looked even better but I questioned my self, how many times am I going to be at 6500 ? When I do the Powertour, I dont want to break and walk home from there or anywhere else.
So I built my 383 combo with forged internals, 6.0 rods, Srp , and the remains of the retro-roller set up but sold my old first design AFR 195 heads and went to the Eliminator set, with longer valve to accomodate the higher spring pressures Harold recommended , and before leaving the factory, had the AFR heads cut to 60 cc chambers and use their premium spring with lightweight retainers. All of this and a decked block put my piston a 0 deck, using a .039 Felpro gasket , my compression came to 10.3. I do run pump premium. Not a big deal as I only drive car some 5-7 k per year , weather permitting.
You have to be truthful with yourself on what your combo needs, not what you want. Hope this helps.

Spames
Jan 15th, 10, 08:43 PM
I'm thinking the 239 :D

I'm not convinced this setup needs a dual pattern cam.

DOUG G
Jan 16th, 10, 07:14 AM
IMO don't get hung up on lift but look at duration.
A bigger motor (383-400+ Vs. 327-355) will swallow a bigger cam taming it down some. So if Stevens car is a 355 and it sounds like that, your car with a 383 will have a milder sound.

Also there are some that run a hybrid cam using a hydraulic roller with solid roller lifters...do a search :)

I know I didn't answer the question and threw in more monkey wrenches...sorry :o

sik68
Jan 16th, 10, 07:33 AM
http://www.airflowresearch.com/articles/article054/A-P1.htm

this is what I based my build off of. This is an article from 03, so if I'm not mistaken the afrs are even better now. Plus, if you did this with a 383, it would be very hard to find a better all-around engine build than this one (in my opinion haha). If you want a street solid roller that's easy on the valvetrain, I wouldn't stray too far from this. The only difference I would think about is maybe going with the air gap instead of the victor jr. In articles and dyno tests I've seen, the air gap always kills the victor in the midrange, and doesn't start giving up hp until around 5500 or 6000

Spames
Jan 16th, 10, 02:09 PM
IMO don't get hung up on lift but look at duration.
A bigger motor (383-400+ Vs. 327-355) will swallow a bigger cam taming it down some. So if Stevens car is a 355 and it sounds like that, your car with a 383 will have a milder sound.

Also there are some that run a hybrid cam using a hydraulic roller with solid roller lifters...do a search :)

I know I didn't answer the question and threw in more monkey wrenches...sorry :o

Well, thanks a lot, Doug! :D

A solid lifters would be great, but for my RPM range, I haven't seen much evidence that it's worth the $400 tab that goes along with it.

Now, if I was starting with a pre-87 block -- I think it's a no-brainer.

DOUG G
Jan 16th, 10, 06:44 PM
Well, thanks a lot, Doug! :D

A solid lifters would be great, but for my RPM range, I haven't seen much evidence that it's worth the $400 tab that goes along with it.

Now, if I was starting with a pre-87 block -- I think it's a no-brainer.
Aren't solid roller lifters cheaper than hydraulics :confused:

Spames
Jan 16th, 10, 09:33 PM
Aren't solid roller lifters cheaper than hydraulics :confused:

Not when you have a factory roller block -- LS7 lifters are just over $100

The comp endure-x lifters are about $450

DOUG G
Jan 17th, 10, 07:29 AM
OOOOoooooohhhh.... LS block :clonk: LOL

Spames
Jan 17th, 10, 10:18 PM
OOOOoooooohhhh.... LS block :clonk: LOL

No, it's a vortec block, but the LS7 lifters are the same as Vortec/LT1

SIDEWAYS
Jan 18th, 10, 10:22 AM
Back to the original topic, if your considering using a SR cam, run the SR cam! The AFR's will like as much cam as you can throw at them. The XR series cams are a true "street roller", and should go many miles w/o issue. SBC's aren't as suseptible to float/bleed-down as the BBC's are, so there probably wont be a huge gain between the HR and SR cam, but there will a power gain regardless due to the more aggressive nature of the SR cam. The XR274 has run low 11's/high 10's in BBC's, cant see why it wouldnt do the same for a SBC.

And by the way, the XR274 should idle better and have more vacuum than the XR288 b/c when you subtract lash from the XR274, that cam is more like a 228/234 HR cam.

BigRed-L72
Jan 19th, 10, 05:35 AM
Perfect candidate for a Hyd roller with a self imposed RPM as decribed !!!
No question there.

Get ahold of UDHarold, his lobe design IMO has everything to do with making a Hyd roller rev.

He will have one custom made for you at CCC. No cookie cutter..off the shelf stuff.

And don`t be afraid to look at a single patten cam or with one that might only have 2-4 degrees more on the exh with those heads.

I`d suggest something around 238-242 @ .050 110 sep
Run 1.6 rockers and you should be set to go.

zdld17
Jan 19th, 10, 09:18 AM
Perfect candidate for a Hyd roller with a self imposed RPM as decribed !!!
No question there.

Get ahold of UDHarold, his lobe design IMO has everything to do with making a Hyd roller rev.

He will have one custom made for you at CCC. No cookie cutter..off the shelf stuff.

And don`t be afraid to look at a single patten cam or with one that might only have 2-4 degrees more on the exh with those heads.

I`d suggest something around 238-242 @ .050 110 sep
Run 1.6 rockers and you should be set to go.

While on the subject of CCC company, I got a flyer the other day from Howards Cam Company that they have aquired CCC. Just wonder if this is Harolds new hide out? Anyone else ?

Spames
Jan 19th, 10, 04:27 PM
CCC?

Comp Cams???

zdld17
Jan 19th, 10, 06:26 PM
CCC?

Comp Cams???

Not sure but when I spoke to Harold, he mentioned at that time, Comp wanted him to come over to their place but would I believe money was not there for it. Maybe things changed now but the flyer did indicate that Howards did take over CCC (Custom Cam Co ) and CCC was the only place that had my address so I think Howards may have gotten the mail list from CCC or Joe Helms from CCC, the guy that actually cut the cam for us. Just hate to see a mind like Harold's go away. Super guy.