Running on 87 octane... Tips an tricks?
Thread Starter
Race Director
Joined: Nov 2000
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From: NC,USA
Running on 87 octane... Tips an tricks?
Hey guys... as a bunch of yall know... I'm working on a whopper parts list!
I need a lil bit of help when it comes to running on 87, I'm not sure my engine plan will...
It contains:
Vortec Cylinder heads 64cc
TRW Forged Flat top pistons/matching rings
Dual plane intake
CompCams 262 Summit # CCA-12-238-2
Self aligning rocker arms
Stock pushrods
And headers
Head gasket is yet to be chosen (http://forums.corvetteforum.com/zerothread?id=663439 )
Thinking about rebuilding the qjet for a second time, and a lars spring kit for the HEI.
Ideally the gearing will let me keep the rpms down on both second and third at 35 and 65-70. So the carb will be adjusted to run off the primarys while on doing both. For extended range between fuel stops :reddevil
Do you think this engine combo will work well on 87? If not, what do yall think needs to be changed for it to love the cheap stuff?
Thanks again :cheers:
I need a lil bit of help when it comes to running on 87, I'm not sure my engine plan will...
It contains:
Vortec Cylinder heads 64cc
TRW Forged Flat top pistons/matching rings
Dual plane intake
CompCams 262 Summit # CCA-12-238-2
Self aligning rocker arms
Stock pushrods
And headers
Head gasket is yet to be chosen (http://forums.corvetteforum.com/zerothread?id=663439 )
Thinking about rebuilding the qjet for a second time, and a lars spring kit for the HEI.
Ideally the gearing will let me keep the rpms down on both second and third at 35 and 65-70. So the carb will be adjusted to run off the primarys while on doing both. For extended range between fuel stops :reddevil
Do you think this engine combo will work well on 87? If not, what do yall think needs to be changed for it to love the cheap stuff?
Thanks again :cheers:
Melting Slicks
Joined: Aug 2003
Posts: 3,416
Likes: 291
From: dayton oh
Re: Running on 87 octane... Tips an tricks? (ZD75blue)
The most important info is missing....................what's your Compression Ratio ???? Are your Vortec heads iron or aluminum?? I can pretty much already guess with 64cc chambers (& iron heads), your engine will not like 87 -- more like 89 or even 92 with any CR over 9.5:1
Alum gives you an extra .5:1 CR to play with before more octane becomes mandatory.
Just my $.02
Alum gives you an extra .5:1 CR to play with before more octane becomes mandatory.
Just my $.02
Racer
Joined: Apr 2003
Posts: 349
Likes: 0
From: Katy TX
Re: Running on 87 octane... Tips an tricks? (ZD75blue)
DONT use stock push rods. Get a good set of hardened ones. I have a buddy that ruined a motor by using stock push rods, it sharpened them like a pencil on the guides. spend the few extra bucks on that. just my 2 cents.
Race Director
Joined: Mar 2001
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From: Living in the Hartland
Re: Running on 87 octane... Tips an tricks? (ZD75blue)
Are you going to run NOS or blower in the in the future? If not I would use hypo piston rather than forged to save some $. The Vortecs are iron heads so depending on the cam you would want a 9/1 comp ration, maybe 9.5/1 if you the cam has long duration and narow lobe seperation.
Thread Starter
Race Director
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From: NC,USA
Re: Running on 87 octane... Tips an tricks? (marshrat99)
The thing on summits site for the pistons says i'll have a 9.72:1 compression with the 64cc heads an flat tops...
Heads are gonna be Iron... unless I win the lottery! Well wait that takes money to get money... guess i'm not winning anytime soon :jester
Heads are gonna be Iron... unless I win the lottery! Well wait that takes money to get money... guess i'm not winning anytime soon :jester
Melting Slicks
Joined: Mar 2001
Posts: 3,365
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From: Lake Villa IL
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St. Jude Contributor
Re: Running on 87 octane... Tips an tricks? (ZD75blue)
Your compression ratio is going to be around 10:1 with that combo. Ask me how I know.
I went with a thicker head gasket to lower compression to below 10. I can run on pump gas, but I've never tried anything in the 80's. I think 91 is the lowest I've run. Given the cost difference, fifteen cents a gallon, it's no big deal, and it's good insurance.
I went with a thicker head gasket to lower compression to below 10. I can run on pump gas, but I've never tried anything in the 80's. I think 91 is the lowest I've run. Given the cost difference, fifteen cents a gallon, it's no big deal, and it's good insurance.
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Thread Starter
Race Director
Joined: Nov 2000
Posts: 16,416
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From: NC,USA
Re: Running on 87 octane... Tips an tricks? (joeveto)
Your compression ratio is going to be around 10:1 with that combo. Ask me how I know.
I went with a thicker head gasket to lower compression to below 10. I can run on pump gas, but I've never tried anything in the 80's. I think 91 is the lowest I've run. Given the cost difference, fifteen cents a gallon, it's no big deal, and it's good insurance.
I went with a thicker head gasket to lower compression to below 10. I can run on pump gas, but I've never tried anything in the 80's. I think 91 is the lowest I've run. Given the cost difference, fifteen cents a gallon, it's no big deal, and it's good insurance.
Alot of the late model stuff can run on regular, but I guess they have aluminum heads too :sad:
Le Mans Master
Joined: Feb 1999
Posts: 6,807
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From: Hoosier
Cruise-In III Veteran
Re: Running on 87 octane... Tips an tricks? (ZD75blue)
I think you have a good shot at 87 octane. With the Vortec heads chamber and gasket for about an 040" quench. Those heads supposedly like a less advanced timing which would be in your favor.
Read these
http://chevyhiperformance.com/techarticles/94138/
http://chevyhiperformance.com/howto/47075/
Read these
http://chevyhiperformance.com/techarticles/94138/
http://chevyhiperformance.com/howto/47075/
Thread Starter
Race Director
Joined: Nov 2000
Posts: 16,416
Likes: 1
From: NC,USA
Re: Running on 87 octane... Tips an tricks? (AlwaysWave)
I think you have a good shot at 87 octane. With the Vortec heads chamber and gasket for about an 040" quench. Those heads supposedly like a less advanced timing which would be in your favor.
Read these
http://chevyhiperformance.com/techarticles/94138/
http://chevyhiperformance.com/howto/47075/
Read these
http://chevyhiperformance.com/techarticles/94138/
http://chevyhiperformance.com/howto/47075/
Thanks for the links... I'm thinking to try the flat tops an if it doesnt like 87 to just retard the timing an make it run on it! :blueangel:
Thread Starter
Race Director
Joined: Nov 2000
Posts: 16,416
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From: NC,USA
Re: Running on 87 octane... Tips an tricks? (Matt Gruber)
i'm at 9.65:1 on 87
tips
1. tight .040 quench
2. cold air
3. no heat riser
you will be about 10:1 :lurk:
tips
1. tight .040 quench
2. cold air
3. no heat riser
you will be about 10:1 :lurk:
Race Director
Joined: Sep 1999
Posts: 11,361
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From: Plano TX
Re: Running on 87 octane... Tips an tricks? (ZD75blue)
I'm at 9.5:1 on my 454. 454's tend to ping more than smallblocks due to older style heads and larger bore. I'm also running aluminum heads and EFI, which helps greatly. I started out with 93 octane. Then tried 89. It ran just as good, no difference at all. Haven't tried 87. I'm also running lots of timing.
Race Director
Joined: Oct 2000
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From: central FL, near the beach.
Re: Running on 87 octane... Tips an tricks? (ZD75blue)
i don't have the air gap as it was not out when i built the motor.
i consider it a necessity on your project, along with cold air. :cheers: and a perfect advance curve
i consider it a necessity on your project, along with cold air. :cheers: and a perfect advance curve
Thread Starter
Race Director
Joined: Nov 2000
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From: NC,USA
Re: Running on 87 octane... Tips an tricks? (Matt Gruber)
Hmm...
My best guess is that with no sharp edges in the chambers or on the piston... I may be able to pull it off!
Wonder what heat range I'll need to run when it comes to plugs! :cheers:
My best guess is that with no sharp edges in the chambers or on the piston... I may be able to pull it off!
Wonder what heat range I'll need to run when it comes to plugs! :cheers:
Melting Slicks
Joined: May 2001
Posts: 2,131
Likes: 4
From: May help you? You can sure as hell try!
Re: Running on 87 octane... Tips an tricks? (ZD75blue)
You might also consider a cam with a little more duration. The later intake valve closing will bleed off some compression at lower speeds where you tend to get in to spark knock, and will gain you a little more top end HP because it allows the engine to breathe better (if your intake and carb are decent) at higher RPMs.
Keep your air and coolant temps low. Use a fresh air induction system and 180' thermostat with a good functioning radiator. Should give you a gain a bit more HP and keep spark knock at bay.
Keep your air and coolant temps low. Use a fresh air induction system and 180' thermostat with a good functioning radiator. Should give you a gain a bit more HP and keep spark knock at bay.
Thread Starter
Race Director
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From: NC,USA
Re: Running on 87 octane... Tips an tricks? (LemansBlue68)
I would change the cam... but the highway rpm's on a stock 75 with a th400 I think might be to low for a cam thats anything bigger then the 262...
But i'm with ya on bleeding some compression down! Thinking about installing the cam advanced a bit so the valves open a tad later...
Thanks for the input, I'll do some reading on the cold air system!
But i'm with ya on bleeding some compression down! Thinking about installing the cam advanced a bit so the valves open a tad later...
Thanks for the input, I'll do some reading on the cold air system!
Thread Starter
Race Director
Joined: Nov 2000
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From: NC,USA
Re: Running on 87 octane... Tips an tricks? (bluevetteman)
Trade the vette for a Honda or a lawn mower. :lol: :lol: