360ci RAISED RUNNER STEELHEAD ENGINE

General engine tech -- Drag Racing to Circle Track

Moderator: Team

perfconn
Member
Member
Posts: 140
Joined: Wed Nov 04, 2009 9:07 am

Re: 360ci RAISED RUNNER STEELHEAD ENGINE

Post by perfconn » Wed Sep 27, 2017 5:49 pm

Because 34* makes good power with no detonation and 33* didn't change anything.

dave brode
Expert
Expert
Posts: 643
Joined: Sun Sep 28, 2008 11:06 am
Location: Frostburg, MD

Re: 360ci RAISED RUNNER STEELHEAD ENGINE

Post by dave brode » Wed Sep 27, 2017 7:27 pm


perfconn
Member
Member
Posts: 140
Joined: Wed Nov 04, 2009 9:07 am

Re: 360ci RAISED RUNNER STEELHEAD ENGINE

Post by perfconn » Wed Sep 27, 2017 7:48 pm

No one is debating the chemistry of a head.The question is about loss of power.Would you rather debate on terminology or try to solve a problem.This is not English 101

User avatar
MadBill
Guru
Guru
Posts: 12620
Joined: Tue Nov 15, 2005 10:41 am
Location: The Great White North

Re: 360ci RAISED RUNNER STEELHEAD ENGINE

Post by MadBill » Wed Sep 27, 2017 9:01 pm

Of the parts changes you mention, I'd say the cam has the highest probability of affecting results. Have you run that exact spec in a smaller bore engine with good results?
Also, although a given head typically flows a little more on a bigger bore, it usually leaves room to step up the intake valve diameter a bit.

BTW, I believe 4.185" is max bore for NASCAR.
Felix, qui potuit rerum cognscere causas.

Happy is he who can discover the cause of things.

perfconn
Member
Member
Posts: 140
Joined: Wed Nov 04, 2009 9:07 am

Re: 360ci RAISED RUNNER STEELHEAD ENGINE

Post by perfconn » Wed Sep 27, 2017 9:18 pm

I have run that exact same intake lobe with good results in a smaller bore.How much smaller and exactly how much better it was I would have to look at my Dyno sheets & build sheets.I do know it was with 6" rods and same size valves.I. also believe it had 1.75 intake rockers and this one has 1.80
I thought when they went to the R07 with 4.5 bore spacing they allowed bigger bores.I know I see 4.200 bores quite often.

User avatar
MadBill
Guru
Guru
Posts: 12620
Joined: Tue Nov 15, 2005 10:41 am
Location: The Great White North

Re: 360ci RAISED RUNNER STEELHEAD ENGINE

Post by MadBill » Wed Sep 27, 2017 9:28 pm

High-effort engines like your are of course very sensitive to changes and you have several here, so I'd start by going back to the exact same spec cam as used in your best power engine, starting with the same indexing that worked best on it. .

The RO7 bore spacing was increased for better cooling, but the max piston diameter is still 4.185"
Felix, qui potuit rerum cognscere causas.

Happy is he who can discover the cause of things.

perfconn
Member
Member
Posts: 140
Joined: Wed Nov 04, 2009 9:07 am

Re: 360ci RAISED RUNNER STEELHEAD ENGINE

Post by perfconn » Wed Sep 27, 2017 9:52 pm

Thanks Bill.I used the bigger intake lobe than I ñormally use because the shorter rod would need it.I'm thinking it could probably use 4* less on the intake but I'm always changing stuff on every new engine to try and find something.It seems like about 705hp & 535 torque is all I can get out of a 360.I've used one of these topend on a 415 and it didn't make any more power.Ton more torque but no more HP.
I've been wrong before and I'm probably wrong on the 4.250 NASCAR stuff.

mag2555
Guru
Guru
Posts: 2065
Joined: Sun Sep 18, 2011 11:31 am

Re: 360ci RAISED RUNNER STEELHEAD ENGINE

Post by mag2555 » Thu Sep 28, 2017 6:23 am

Why the Hell are your air to fuel ratios swinging around by some 20gph at some rpm ?!!!

Man between 7200 and 7400 your going from .23 to over .40, that's huge!

RCJ
Expert
Expert
Posts: 566
Joined: Wed Jul 25, 2007 6:15 am
Location: Oklahoma

Re: 360ci RAISED RUNNER STEELHEAD ENGINE

Post by RCJ » Thu Sep 28, 2017 6:28 am

You when from a 6.00, 530 gram rod to a 5.85, 570 gram rod I would expect lower peak hp from those changes.Were your heads new or refresh?

Warp Speed
Guru
Guru
Posts: 2061
Joined: Wed Jun 25, 2008 1:46 pm
Location: NC

Re: 360ci RAISED RUNNER STEELHEAD ENGINE

Post by Warp Speed » Thu Sep 28, 2017 8:10 am

Maybe I misunderstood, but the op went to a shorter stroke AND a shorter rod?
BTW, the max bore size in cup is 4.185, and a max ci of 358.
4.195 in Xfynity and Trucks with a max ci of 360.

4.195 us about as big as you can get away with in the casting, as even though they have a 4.5bs, they are not Siamese, and have water running between the cylinders for cooling during extreme temps.

perfconn
Member
Member
Posts: 140
Joined: Wed Nov 04, 2009 9:07 am

Re: 360ci RAISED RUNNER STEELHEAD ENGINE

Post by perfconn » Thu Sep 28, 2017 10:01 am

Warp,
Yes I went with a shorter(3.27) stroke & a ( 5.85) rod length & 4* more on intake duration.Looks like it didn't work but don't know why.
RCJ,
Yes shorter rod should have lowered peak torque but I think bigger cam messed me up.
Mag2555,
Don't know why BSFC varied so much but it never got in the twos.Don't have any A/F ratio readings on the Dyno unfortunately.

DaveMcLain
Guru
Guru
Posts: 2676
Joined: Thu Jan 06, 2011 8:57 am

Re: 360ci RAISED RUNNER STEELHEAD ENGINE

Post by DaveMcLain » Thu Sep 28, 2017 10:12 am

perfconn wrote:Warp,
Yes I went with a shorter(3.27) stroke & a ( 5.85) rod length & 4* more on intake duration.Looks like it didn't work but don't know why.
RCJ,
Yes shorter rod should have lowered peak torque but I think bigger cam messed me up.
Mag2555,
Don't know why BSFC varied so much but it never got in the twos.Don't have any A/F ratio readings on the Dyno unfortunately.
When you added more rocker and more duration to the engine did you run it through some lash loops on the dyno? If so what did that tell you?

I don't think that the differences in the stroke and rod length will make that big of a difference.

perfconn
Member
Member
Posts: 140
Joined: Wed Nov 04, 2009 9:07 am

Re: 360ci RAISED RUNNER STEELHEAD ENGINE

Post by perfconn » Thu Sep 28, 2017 10:55 am

Dave,
Yes tried lash loop but no real changes showed up.I don't think it was any one change.Shorter rod should have lowered peak but maybe bigger cam offset it.I have run 4.185 by 3.27 before in Brodix Track 1 Spec heads and won back to back SRRS regional championships so I don't think it's the bore stroke deal but maybe adding in the bigger cam and shorter rod screwed up something.

DaveMcLain
Guru
Guru
Posts: 2676
Joined: Thu Jan 06, 2011 8:57 am

Re: 360ci RAISED RUNNER STEELHEAD ENGINE

Post by DaveMcLain » Thu Sep 28, 2017 11:43 am

What about the exhaust system used in the testing was it exactly the same? I've seen an old rusty on the inside set of headers take away that much power on a 450 horsepower engine before in back to back testing.

Tuner
Guru
Guru
Posts: 1890
Joined: Sun Apr 01, 2007 5:26 am

Re: 360ci RAISED RUNNER STEELHEAD ENGINE

Post by Tuner » Thu Sep 28, 2017 2:51 pm

mag2555 wrote:Why the Hell are your air to fuel ratios swinging around by some 20gph at some rpm ?!!!

Man between 7200 and 7400 your going from .23 to over .40, that's huge!
It looks like you have the time between RPM steps mixed up with BSFC. Where am I missing fuel GPH info? I don't see that.

However you're right, the BSFC is erratic. It is anomalous between 6200 and 7200 and particularly it is crazy between 6600 and 6900 where the power backs up 15 HP and recovers. Carbs with too much air bleed do this if they have too large MAB or too large or too many E-Bleeds.

Post Reply