850 HP Buick 525

Had a chance to dyno this beast again the other day.. As some of you know, this is George Sweesy's motor, that I originally built for him in '03.. while we had it apart for a freshen up, we made some changes and picked up quite a bit of power.. I figured you guys might be interested, I don't post much dyno info anymore because it's mostly "more of the same" but this one is definately out of the norm..



Been a while since I talked about this thing, so here is a tech rundown.

76 Buick Stock Block, filled, TA Lifter and Block girdle, Billet main Caps.
Custom overhead oiling system based on a Dave Mongeon design. Moroso external oil pump.
Moldex 4.400 stroke Billet Crankshaft- Internal Balanced.
6.925 GRP Aluminum Rods (TA 1631)
JE Stroker pistons, Flatop with 9CC notches, 4.360 bore
Custom TSP Windage Tray
SRE Custom Tube chassis oil pan
TSP custom Front, Midmount, and accessory engine plates.
TA Timing cover.
TA Stage 2 TE heads, TSP ported, 370cfm, 2.260 Intakes
TA Custom Roller cam- 283/285 @.050 duration, .695/.715 lift 108 LC
Compression- 15.17 to 1
Custom Made Tunnel ram intake manifold
(2) 9375 1050cfm Holley Dominator carbs
TSP custom vacuum pump system
MSD billet Dist, secondary wires. NGK Spark plugs
TA SFI Flexplate

Session went smoothly, we were very happy with the results of some oil system work on the pump inlet side, as well as the function of the new tunnel ram, cam, and compression increase. Last incarnation of the motor was 13.25-1. We picked up a solid 50HP with the changes.

Only problem we had is that we found the limits of dynoing an engine thru the flexplate. Because it's internally balanced, and I don't have a flywheel for it, we dynoed thru the setup that my dyno guys has used on many, many engines, which involved 3 bolts thru the converter bolt holes, and then 3 1" spacers to the reaction plate for the Superflow SF902 dyno.

We have done many, many 600 and 700 HP BBB's thru this setup, and Ron has done hundreds of other motors, never had a problem. We did this motor at around 800 HP many times, with no problems. But this time around, on the 3rd pull, it broke one of the 3/8 bolts, which took the oil line off the back of the engine and caused a few tense moments.. but it was no big deal, we replaced the fittings, and Ron upgraded the mounting setup to 7/16 bolts.

Did two more pulls, fooling with timing, which produced the sheet below.. The vacuum pump system was not in use here, in the past it has added right about 10-12 HP.



We hooked up the vacuum pump for the last pull, but only got to 6000 rpm before it broke free of the mounting again, breaking the 7/16 bolts this time. :eek2:

But as the sheet shows, it was up subtantially with the pump working.. probably would have been right around 855-860 HP..

Here is that partial sheet



It was too late in the day to fix the mounting and oil line damage again from breaking those bolts, and we had seen what we needed to see..

It's sitting comfortably in my engine room now, as I finish a chassis upgrade to SFI 25.5 and installing a bunch of fiberglass on George's car.

Should be fun..

 

verry nice. :TU:

 

WOW!:eek2: Now that's a motor that seperates the men from the boys. Nice Job.

 

Jim

How many inches vac were you pulling at 6000?

WJ says 12" is the sweet spot. I have found on 2 different engines, the first an 800 hp 494, and the second a 780 horse 494, that at 8" we picked up 12 hp and at 12" we picked up 18 hp from around 4500 on. At around 15" it started sucking the valve cover gaskets in. Gains on both engines were almost identical. Of course the better the engine is sealed up the better the vac pump will perform, not that George's isnt sealed as I'm sure it is tight as a drum. We had a Moroso pump. Also an interesting discovery pretty much by accident, the pump freed up a couple more HP pulling from the rear of the intake than from a valve cover which may not be worth the hassle, but hey, a couple is a couple. These were both engines we spun to 6500.

I dont know what his car weighs, but it should be fun with this mill.

 

Jim,

Nice job!!! I cant wait to see George out racing with it!

Vacuum pumps are a bit scary. When going through the mph traps and letting off the gas you still have quite a bit of vacuum and then no rpm to keep up the oil pressure. Therefore you will see a significant drop in oil pressure which is scary. For this reason I keep my vacuum around 8".

Thanks for posting the dyno results!


Later

 

Somebody made a deal with the Devil!! That motor is the sickest thing i've seen N/A. Lottery ticket, here I come! How fast would this put a full bodied skylark in the 1/4 mile out of curiousity? Well done on yet another great Buick motor, Jim. :3gears: :kodak:

 

Jim,

We found in prior testing that 8" was what this motor wanted.. beyond that, HP increase was minimal, the only real affect we saw was on oil pressure. Therefore it has a pressure relief valve set at 8" in the RH valve cover, and it was pulling that steadily from the start of the dyno test at 4700 rpm.

We did increase the moroso oil pumps pickup from a -12 to a -16, which included a new Pickup from Steve at SRE, as well as welding the inlet fitting right to the pump, since it was only a -8 o-ring fitting as designed. This was the only change to the oiling system from before, and it looks like we nearly doubled the available pressure thru the pulls. It easily maintains 115-125 psi without the vacuum pump now, that drops to just under 100 with the vac pump working.

John,

Yes, early on we experienced a "flash" from the oil pressure pro light on decel, and found that if the engine rpm was kept up around 2500, we didn't get that.. I beleive this is directly related to the vacuum pump, although there is a fairly complex senario that can be happening here.

JW

 

I will be able to answer that question later this month.. as it goes in the car in my Avatar..

At 3200 lbs, that car as gone 9.30 with a single 4, making 804 HP on the same dyno.

I am in the process of installing a complete fiberglass front end, doors and rear bumper on the car. Also a new hood scoop with a better design than the old one, and updating the tube chassis to SFI specs to certify it to 7.50 et.

We figure it will weight about 2900 with driver when it's done.

JW

 

JW: Nice looking intake and carbs. Where did you get those from ? Guess I should have kept it ! (Just kidding). Glad to see everything went well. Ken

 

JW/Thanks for all the great info.My first Impression was nice valve covers
OK,now back to the HP talk

 

Hmm....
840+ HP - check
Fiberglass front end, doors, and rear bumper - check
Newer, better scoop - check
2900 lbs w/driver - check
I'm guessing 9-teens to 9.0s on a crappy day. 8.90s on a decent day, 8.80s on a good day. Awesome day, who knows? 8.70s perhaps? That's my educated guess.

 

I was talking to George in Columbus, and you're dead on, Doug....that's right where George is hoping to hit.:3gears:

 

Jim, how fast do you think my 1600# dragster would go with that motor? I figure I've got around 525hp now and it runs 8.40's @ 156 mph. I don't know if want to drive it with that motor, its almost a handfull now. Scott

 

Jim, Words fail me.....JUST AWSOME comes to mind.

 

Hey Cole, I hope you got my "tongue in cheek" humor. Even though I said "educated guess", it really wasn't a guess on my part. Everything I noted with a "check" is stuff that I've done to my car the last few years, and that's what it runs in those conditions. The only thing holding George's car back up 'til now has been the weight, which is now disappearing!

 

Yeah, I got the humor....I'm not quite as slow as I look (although you may get some contrary opinions there!:laugh: ). The 'glass will definitely help ...plus George, uh, like you, um.....well, yeah...weight loss helps!:3gears:

 

Cant wait to get back from turkey and spend that money....btw how much are we lookin at there if you dont mind ballparkin???

 

I think George just decided to use one of my "Tri-Shield-- Get One Engine Free " coupons.

 

I say we drop that mill into Mr. Lore's black convertible with a big PS scoop and go have some fun! :grin:

 

Easily twenty grand.