331 dyno

gtcoupe65 · 06-12-2003, 11:06 PM

Finally got my little stroker dyno'd yesterday, here are the results:
http://eastsiderental.com/dyno.html
Anyone have comments/suggestions? Stats are as follows: 289 block bored .030 over, Scat 9000 crank, Scat h beam forged rods, Probe 10.4:1 pistons, Vic Jr intake, Comp 284H cam, Twisted Wedge heads, Proform vac carb on holley 3310 base. Me thinks I'm over cammed a bit (yeah, some of you guys said it would be).

_________________
65 GT coupe restomod w/302, Torker 289,
TFS twisted wedge, track heat cam, Strip Annihilator, T5, 9in 370 tracloc, flowmaster 2 chambers on 1 5/8 headers...on and on

[ This Message was edited by: gtcoupe65 on 6/13/03 11:23am ]

[ This Message was edited by: gtcoupe65 on 6/13/03 11:24am ]

[ This Message was edited by: gtcoupe65 on 6/13/03 11:24am ]

[ This Message was edited by: gtcoupe65 on 6/13/03 11:25am ]

mstngjoe · 06-13-2003, 12:06 AM

Nice numbers.

Is that the XE 284 H?

Looks like something happened about 5800.

gtcoupe65 · 06-13-2003, 12:19 AM

Yes, its the version using the 351 windsor firing order. I noticed the dip at 5800 too, it appeared on all 8 runs, have no idea what caused it. Had quite a time getting the air/fuel ratio to a safe level at 4500. We think it was the rush of air when the secondaries opened up.

67stang · 06-13-2003, 12:18 PM

what is the cfm on that carb? I'd expect about 15 more HP and 15-25 more lb.ft of torque with that combo and a 750 double pumper.

Did you play with timing and jetting? There is definately more in that motor with tuning.

gtcoupe65 · 06-13-2003, 12:30 PM

The cfm is I assume a good bit over 750. The carb consists of a proform 750 body on a holley 750 baseplate with 3310 bowls, 31 shooter, ended up with 70 main jets and 75 secondary jets. This is a vacuum secondary carb, using the long yellow spring. Pump cam is the blue one installed in the #2 hole. On the first run I got about 350HP (349.7 to be exact) and about 316 Ft lbs., but the a/f ratio was pretty lean at two or three points on the RPM scale. This was with 67 main jets and 76 secondaries. Total timing was 40 during all runs. We jetted primaries, made two runs, then jetted up secondaries to final settings. Any suggestions are appreciated (I've already ordered a ram air kit).

bluestreek · 06-13-2003, 07:47 PM

I run a Holley 750 HP which has the same type of mainbody as yours and I have to use 74 jets in the front and 84 in the rear for good power. That fancy mainbody flows a lot of air and needs a lot of fuel. I also run 18 degrees of idle advance and 37 degrees of total advance, all in by 2500 rpms. A 1" 4 hole spacer was worth 5 HP. My 331 tries break the 26" DRs loose at 60 mph on dry pavement!

yellowbilly · 06-13-2003, 09:58 PM

Were you happy with these guys? I am building a 408W that I would like to get dynoed. Do you work at eastside rentals?

gtcoupe65 · 06-13-2003, 09:59 PM

Bluestreek, I envy your hood! I only ahd room for a 1/2" open spacer. I added a dynojet printout of my air/fuel ratios for the two runs to my original link, here it is again www.eastsiderental.com/dyno.html
I'm curious if you've checked the ratio's on your setup. It sounds like you're running quite a bit richer than me, although I really don't know what effect your dual plane intake would have compared to my single plane. I do think the Vic Jr is probably costing me some torque, I was supposed to have a Stealth 8020 on in time for the dyno test, but it's arrival has been delayed. Still intend to try it when it arrives. I sure appreciate your comments and or suggestions, you've got quite a bit of experience on me with these 331's. Interesting little buggers though, aren't they!

gtcoupe65 · 06-13-2003, 10:02 PM

Yellowbilly, yes I not only work there, I own the company along with my brother. Our dad started the place in the late 1950's and we worked there as kids through college, went into real careers elsewhere, then came back as owners about 20 years ago. Still having a ball there, it's the only way I can support my need for speed!

_________________
65 GT coupe restomod w/331, Vic Jr,
TFS twisted wedge, Proform 750, Comp XE284H cam, MSD 6A, Pertronix, T5, 9in 370 trutrac, flowmaster 2 chambers on 1 5/8 headers...on and on...too much is never enough

[ This Message was edited by: gtcoupe65 on 6/14/03 10:03am ]

gtcoupe65 · 06-13-2003, 10:08 PM

Yellowbilly, the dyno isn't at our facility, I used the one at Carburetor and Fuel Injection Connection www.carbconn.com at Totem Lake just north of Kirkland. I've used them on a couple other engines. They're not cheap, but I think they're very thorough. Good guys, very knowledgeable, even if they are mopar nuts!

_________________
65 GT coupe restomod w/331, Vic Jr,
TFS twisted wedge, Proform 750, Comp XE284H cam, MSD 6A, Pertronix, T5, 9in 370 trutrac, flowmaster 2 chambers on 1 5/8 headers...on and on...too much is never enough

[ This Message was edited by: gtcoupe65 on 6/14/03 10:09am ]

bluestreek · 06-14-2003, 01:00 AM

From looking at the A/F graphs, it does look like the power drops off when the mixture falls lean. Looks like you need to work on that.

Thanks for posting the dyno charts!

Good luck with your new toy!

gtcoupe65 · 06-14-2003, 09:01 AM

Bluestreek, our combo's are pretty similar with the exception of the intakes. I think I'll try jetting up a couple numbers on the primaries and see what the ass meter says. Thanks for all the input.

EricG · 01-28-2004, 11:45 PM

That dip in the power levels at 5800 RPM could be due to valvespring harmonics causing a loss of valve control. From what I've read, it seems to happen between 5000 & 6000 RPM. I know it sounds weird but do a search on "Comp beehive springs harmonics" and you'll see what I mean.

gtcoupe65 · 03-21-2004, 11:49 AM

Ran it again, this time on a Mustang dyno. Had to put a big guy on the trunk to keep the wheels from spining. The only changes from last time was addition of 4.33 gears and reduction of 5 degrees total timing. On the Mustang dyno it topped out at about 310 HP and 292 torque at 5700/4750 rpm. The additional loading on the Mustang dyno makes for some disappointing numbers, but I felt pretty good after seeing a turbo'd 350 Chebby run about 5 hp and ft#s LESS!

mstngjoe · 03-22-2004, 04:03 PM

Add about 10% to that!