Go Back   Corvette Forum > General Corvette Topics > Engine Mods
Sign in using an external account
Register Forgot Password?
Register Search Today's Posts Mark Forums Read FAQ Vendor Directory
Search
Engine Mods
Outrageous Builds, High-Horsepower Modifications, strokers, and big cams for the Corvette Sponsored by
CARiD

Welcome to Corvetteforum.com!
Welcome to Corvetteforum.com.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, at no cost, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, join Corvetteforum.com today!


Corvette Store
 
 
C7 Parts & Accessories
C6 Parts & Accessories
C5 Parts & Accessories
C4 Parts & Accessories
C3 Parts & Accessories
C2 Parts & Accessories
C1 Parts & Accessories
Wheels & Tires
Sponsored Ads
 
 
Vendor Directory
  
Reply
 
 
 
 
Thread Tools Search this Thread
Old 05-22-2003, 11:24 PM   #1
l78vetteman
CF Senior Member
 
l78vetteman's Avatar
 
Member Since: Oct 2001
Location: Austin TX
Default How much HP gain from Roller Rockers?

I am looking at the June Hot Rod magazine. Nice article on BB engine build up. In the side bar regarding Crane Roller rockers (page 39), they comment about a typical HP gain of 5 - 8 HP with the addition of RR based on previous engine build ups ( i assume they have dyno number to substantiate). I see several bits on information suggesting 15+ HP gain from RR. What is the scoop? Is 15+ and marketing number so that we all go buy a set? If the gain is only 5 to 8 HP, I would stick with the stock rockers and save my money.

BTW, I am building a 396 / 425 HP engine for my 65. I am looking for an easy 25 HP gain. Any suggestions?

Thanks,
l78vetteman is offline   Reply With Quote
Old 05-23-2003, 09:42 AM   #2
Engo
Junior Member
 
Member Since: Apr 2003
Location: Stockholm
Default Re: How much HP gain from Roller Rockers? (l78vetteman)

I donīt think there is a gain from the rollers that you actually can measure with a dyno. The theoretical gain would come from reduced friction.

But the thing is that roller rockers usually have a slightly bigger ratio than a stock rocker. This makes the dyno comparison inconclusive when it comes evaluate the effect of the reduced friction itself. Claims like + 5, 10 15 20 hp are, because of this, nothing but marketing in my opinion.
If there is an actual increase it is most likely due to the roller having a higher ratio than the one it is compared too. Even if the manufacturer state 1:5 ratio they actually are more, often as much as 1.55. On top of that, stock rockers usually have less ratio than they are supposed to have making the comparison even more screwed.
I have a set of Harland Sharp alu roller rockers. The manufacturer say they are 1.65 ratio. However, I have measured the ratio and it is 1.74!!!
I also have a bunch of old stamped steel rockers that are supposed to be 1.5 ratio. I have measured a couple of them too just for fun. They measure between 1.45-1.5 in ratio!!

But of course roller rockers do have a use and that is in applications with high valve spring pressure. :D


[Modified by Engo, 2:43 PM 5/23/2003]
Engo is offline   Reply With Quote
Old 05-23-2003, 09:31 PM   #3
l78vetteman
CF Senior Member
 
l78vetteman's Avatar
 
Member Since: Oct 2001
Location: Austin TX
Default Re: How much HP gain from Roller Rockers? (Engo)

Engo'
Thanks for your comments.
rob
l78vetteman is offline   Reply With Quote
Old 05-23-2003, 09:47 PM   #4
Vetterodder
CF Senior Member
 
Vetterodder's Avatar
 
Member Since: Feb 1999
Location: Fountain Hills AZ
Default Re: How much HP gain from Roller Rockers? (Engo)

I agree with Engo. If you read those ads closely, they don't seem to mention any reference to ratios, only that their product increased power. Some of the power increase does come from reduced friction but I suspect that most of it comes from the increased ratios.
Vetterodder is offline   Reply With Quote
Old 05-23-2003, 11:26 PM   #5
l78vetteman
CF Senior Member
 
l78vetteman's Avatar
 
Member Since: Oct 2001
Location: Austin TX
Default Re: How much HP gain from Roller Rockers? (Vetterodder)

Vetterodder,
Another Stockton guy! I grew up in Stockton (actually in Morada) and still remember when you could run at Kindon Drag strip. Did a bit of street racing with my 13 sec Chevy Nova 25 years ago...

My folks are still in town.

Take care,
Rob McPherson
l78vetteman is offline   Reply With Quote
Old 05-24-2003, 10:57 AM   #6
vader86
CF Senior Member
 
vader86's Avatar
 
Member Since: Sep 2001
Location: Madison AL
Default Re: How much HP gain from Roller Rockers? (l78vetteman)

All i can say is that for C4s, 1.6rr typically give us 10-15hp, measurable on dynos.

Someone just tried 1.7s on their modded motor and got 17hp, If i recall.
vader86 is offline   Reply With Quote
Old 05-24-2003, 11:12 AM   #7
Taijutsu
CF Senior Member
 
Member Since: Apr 2002
Location: Stockton Ca
Default Re: How much HP gain from Roller Rockers? (l78vetteman)

I can't comment on BB. On my 74 SB the 1.6 rrs made the engine run cooler and the "sweet spot" went from 2800 to 3000 rpm. Those that have dynoed their engine usually report 8-12 hp gain.
Rick
Taijutsu is offline   Reply With Quote
Old 05-24-2003, 12:47 PM   #8
l78vetteman
CF Senior Member
 
l78vetteman's Avatar
 
Member Since: Oct 2001
Location: Austin TX
Default Re: How much HP gain from Roller Rockers? (Taijutsu)

Rick,
I would guess that the big difference in your application is the change from 1.5 to 1.6 ratio - like putting in a higher lift cam shaft with slightly more duration.

As suggested by others in this thread, the increased ratio is likely the bigger effect.

Rob
l78vetteman is offline   Reply With Quote
Old 05-24-2003, 01:01 PM   #9
Taijutsu
CF Senior Member
 
Member Since: Apr 2002
Location: Stockton Ca
Default Re: How much HP gain from Roller Rockers? (l78vetteman)

No flames here! Gaining approx .030 lift for 2 deg more dur is a nice trade. I was more impressed w/lower temps. My engine ran at least 10 deg cooler under high temps w/AC on! For stk C3s I highly recomend this change for both reasons.
Rick
Taijutsu is offline   Reply With Quote
Old 05-25-2003, 01:06 PM   #10
CFI-EFI
CF Senior Member
 
CFI-EFI's Avatar
 
Member Since: Sep 2000
Location: The Top of Utah
Default Re: How much HP gain from Roller Rockers? (l78vetteman)

These later comments seem to be indicating power gains and rpm "shifts" from a switch from 1.5:1 stock sbc rockers to 1.6:1 roller rockers. The gain/change is more a result of the increase in ratio than the change to roller rockers. The initial comments, citing minor or negligible power gains, seem to be more on the mark, where a ratio change is not involved. Roller rockers DO reduce friction and can produce very minimal power gains. The biggest advantages *I* see are a more accurate rocker ratio, slightly lower oil temps, and lower valve stem/guide wear. The big block you are building has a 1.7:1 ratio, stock. For the engine you describe you are building, increased rocker ratio probably isn't worth the added stress a 1.8:1 rocker would impose. Rollers won't give you the power increase you're looking for, but they will provide the cited benefits. Good luck, and...

RACE ON!!!
CFI-EFI is offline   Reply With Quote
Old 05-25-2003, 05:59 PM   #11
wallyknoch
CF Senior Member
 
wallyknoch's Avatar
 
Member Since: Jun 2002
Location: Dearborn mi.
Send a message via AIM to wallyknoch
Default Re: How much HP gain from Roller Rockers? (l78vetteman)

Probably ZERO. Did you ever read a Mid America book and see how much horsepower can be bought over the counter by there adds. I went page by page through out the book and came up with over 1000hp with just bolt ons. Thats a Baghdad Bobs intelligence. On the 396 engine, a little taller solid lifter cam, and matching the ports would be a better choice than roller rockers. :D
wallyknoch is offline   Reply With Quote
Old 01-13-2011, 11:17 PM   #12
porchrd
PORCHRD
Support Corvetteforum!
 
Member Since: Jan 2011
Location: Castaic California
Richard Betters
Default

Hey Guys:

What are the real engine UPGRADES that one can attain on the C-5 2004 Z-06 aspirated
engine.

I was told that you do not mess around with computer chips is this fact or just blowin
smoke.

I have owned 8 Corvettes in my 68 years and now with all of this high technology that is
in these cars today I am pretty much lost.

I guess I am like Tim Allen on Home Improvement always wanting to make more H.P.
I have never dealt with the juice but I have had supercharger experience in the past.

It has been 14 years now since my last Vette 1990 yellow 6-spd convert and now I am once aagain a proud Corvette owner and loin it.!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!

I hope you Vette owners will share some our knowledge and experience on your Z-06
engine upgrades.

Thanks to all of you

porchrd
porchrd is offline   Reply With Quote
Old 01-18-2011, 04:19 PM   #13
dankhts
CF Senior Member
 
dankhts's Avatar
 
Member Since: Jun 2004
Location: Stoney Creek Ontario
Default

Quote:
Originally Posted by CFI-EFI View Post
These later comments seem to be indicating power gains and rpm "shifts" from a switch from 1.5:1 stock sbc rockers to 1.6:1 roller rockers. The gain/change is more a result of the increase in ratio than the change to roller rockers. The initial comments, citing minor or negligible power gains, seem to be more on the mark, where a ratio change is not involved. Roller rockers DO reduce friction and can produce very minimal power gains. The biggest advantages *I* see are a more accurate rocker ratio, slightly lower oil temps, and lower valve stem/guide wear. The big block you are building has a 1.7:1 ratio, stock. For the engine you describe you are building, increased rocker ratio probably isn't worth the added stress a 1.8:1 rocker would impose. Rollers won't give you the power increase you're looking for, but they will provide the cited benefits. Good luck, and...

RACE ON!!!
minimal gains, but they can enhance your other mods and even allow you to make additional mods by allowing more precise valve train control........and stability... I have them in my C5, I like them, also have a set of them in our '88 Iroc 355 TPI, like them there too... they go along well with the other mods the engines have...
dankhts is offline   Reply With Quote
Old 01-21-2011, 07:16 AM   #14
wingjohn2
CF Member
 
Member Since: Jun 2007
Location: butte montana
Default

marketing...how to twist the truth to meet your goals. Same twisted truth is involved with all the phoney octane boosters on the market.
wingjohn2 is offline   Reply With Quote
Old 01-31-2011, 10:32 PM   #15
Manuel Azevedo
CF Senior Member
 
Manuel Azevedo's Avatar
 
Member Since: Jan 2007
Location: Concord Calif
Default

Well can't really say how much but you will get more valve lift at the same advertised ratio. That is compared to stock stamp steel rockers. The stock rockers decrease ratio as they slide back via the slot in the bottom of them. granted even rollers have a decreasing ratio as the tip moves closer the the stud but no where near what the stock ones do.
Manuel Azevedo is offline   Reply With Quote
Old 01-31-2011, 10:32 PM
 
Go Back   Corvette Forum > General Corvette Topics > Engine Mods
Reload this Page How much HP gain from Roller Rockers?
 
 
 
Reply

Tags
18, 396, big, block, c5, corvette, gain, gains, harland, horsepower, hp, increases, power, rockers, roller, sharp


Thread Tools Search this Thread
Search this Thread:

Click for Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Forum Jump


All times are GMT -4. The time now is 10:32 PM.


Emails & Password Backup

Search Engine Friendly URLs by vBSEO 3.5.2