Well, I've been on the dyno again. I had been disappointed with the previous dyno facility that I used for my first few days of dyno tuning (they did not have all the sensors that a centrifugal supercharger blow through carb setup should be data-logging, and they seemed a little lost on my engine), so this time I booked a day at the Vrbancic Bros Racing dyno - these guys are good! Especially considering how mild an engine setup that I have.

Basic engine:
468 BBC, 8.32 compression, out of the box Canfield 310 heads, base Comp blower cam - .547/.547 lift 232/327 duration 114 degree center installed at 112 degrees, Chevy L78 dual plane intake, 830 Holley by The Carb Shop. ProCharger D2-R centrifugal supercharger.

The third pull of the day was the first full n/a pull done without the blower attatched, just to get a baseline feel. Keep in mind that the carb was NOT optimized for n/a operation. 35 degrees advance

RPM CBTrq CBPwr
3500 507 337.5
3600 508 348.4
3700 509 358.4
3800 508 367.4
3900 508 377.1
4000 508 386.9
4100 510 398.1
4200 512 409.1
4300 513 420.1
4400 513 429.6
4500 511 437.8
4600 506 443.6
4700 501 448.1
4800 496.2 453.5
4900 492.1 459.1
5000 489.9 466.4
5100 486 471.9
5200 479.9 475.2
5300 473.2 477.5
5400 465.6 478.7
5500 457.4 479
5600 449.3 479
5700 442.6 480.4
5800 434.4 479.7
5900 424.9 477.4
6000 414.5 473.6
--------------------
Avg 485.3 435.1

The 14th pull of the day was the best on pump gas. OK, really it wasn't the best pump gas pull, but you'll have to wait until public release of an under development part that boosted max hp to ~ 770 hp. It maxed out at ~ 10.5 psi boost (I would give you guys all the data, but the data disk I brought home got corrupted). Of note: this run was with a West Coast Fab hat for the carb, which on earlier pulls in the day proved to be worth 41 hp over a two inch riser and the ProCharger hat. Of extra note: this was WITHOUT an intercooler, the intake manifold air temperature only reached 98 degrees - which I think vindicates my choice of a large centrifugal that is spun slowly to keep from overheating the intake air.

RPM CBTrq CBPwr
3000 574 328
3100 584 345
3200 593 361.3
3300 599 376.6
3400 605 391.7
3500 611 407
3600 621 425.5
3700 632 445.3
3800 641 463.8
3900 651 483.5
4000 663 505
4100 671 524
4200 679 543
4300 686 562
4400 689 577
4500 692 593
4600 694 608
4700 695 622
4800 696 636
4900 697 650
5000 699 665
5100 700 680
5200 701 694
5300 697 704
5400 695 715
5500 693 726
5600 689 735
5700 682 740
5800 675 746
5900 665 747
6000 659 753
------------------
Avg 662 573

The 25th run of the day we maxed out the installed fuel system - the dyno pull was shut down early at 5800 rpm because the fuel system was at its limits. With some changes in the fuel system and carb setup it would have easily crested 1,000 hp. The max boost was ~ 17.1 psi, we used a faster blower pulley. (I'll get a new uncorupted data disk tomorrow, sorry I can't post more data at this time). This was also non-intercooled, my data disk is corrupted, but I believe the intake manifold air was at 143 degrees. Of course this pull was on 116 octane fuel. I'll probably never race it at this level, but I was curious what would happen with proper fuel and more boost.

RPM CBTrq CBPwr
3000 605 345.7
3100 620 365.9
3200 633 385.9
3300 646 405.7
3400 658 425.8
3500 673 448.2
3600 694 475.9
3700 708 498.6
3800 725 524
3900 739 548
4000 749 571
4100 761 594
4200 773 618
4300 785 643
4400 796 667
4500 805 690
4600 814 713
4700 825 738
4800 833 761
4900 842 786
5000 853 812
5100 860 835
5200 860 851
5300 860 867
5400 858 883
5500 860 900
5600 862 919
5700 863 937
5800 861 951
------------------
Avg 723 618

I learned a lot today. I was also relieved that my engine has now made it through ~ 40 dyno pulls without much drama. We did discover an interference between one rocker arm and my choice of valve covers. Also, my HEI distributor blew up today, (fortunately just when we were starting the engine for a dyno pull), so we popped an MSD in place. My original fuel regulator, a Mallory piece, could not flow enough fuel volume so I got a Product Engineering fuel regulator.

Thanks in part to the use of the West Coast Fab carb hat and the installation of a 1" spacer under my carb my engine now has very even fuel trim in all the cylinders, the EGT's were great, and the A/F ratios were nice too. Once again, I'll get some uncorrupted data tomorrow with all the details.

Many thanks to George and Bob Vrbancic, O.J., and Ted for all their work today. It was amazing to watch how quickly they went through tuning ideas to bring the engine to the next level.

 

WOW thats some awsome numbers, I wish there were companies around here with that kind of parts and ideas just laying around. The best we have up here still does not even come close to what you just described. You have me intrested in the development of your engine. Any more pulls to come? lets see her push 1k. Gonna have to start a 1k hp corvette club soon.

 

All I can say is for you to contract with some shop like Vrbancic Bros Racing and ship the engine back and forth if you need to. At this power level any bad guesses will result in scattered engine pieces.

I have no current plans for more tuning or parts changes, the C16 + more boost dyno pull was just for fun - I can't even use the "mild" 753 hp pump gas tune.

I really don't think there is much interest in the CorvetteForum for a 1,000 hp club - only a few guys here will ever play or drive at that power level.

Thomas

 

Wow, the numbers keep getting better! Even more impressive than last time. You sure have picked a combo that works. Getting the blower to work through a carburetor is not an easy thing to do, but you seem to have found the right tricks.

Are there higher numbers to come or is this ready to put in your car?

Steve

 

Just another testimont to properly tuned boost, wow. Where is that dyno shop located. I have a friend that is building a pro street Road Runner (He is the guy at the Friday night show with the Red Challenger, All Indy top end) One of the options being considered is a blown 426 Hemi. I am trying to talk him into a centrifical blower. I copied your dyno run and will show it to him. Both of us are novice blower motor guys, so would the shop be able to point us in the right direction regarding proper hats to use, etc, etc. If we could pull 950 Hp out of a 426 Hemi on race gas, that would be plenty of power.


[Modified by 69 N.O.X. RATT, 6:16 PM 2/8/2003]

 

Those are really impressive numbers and if you would have spun it a little tighter you might have topped the 1000 horse mark. Also you are putting out that power with only a single 830 carb.
I would love to see the boost levels. Rpm vs Boost. I think a centrifugal supercharger's boost is rpm related. I woud love to see a comparison.
Anyway very nice job. :) :)

 

Ratt, be sure to tell Bob and George that I sent you, here is the contact info:

Vrbancic Bros Racing
1463 E Philadelphia
Ontario CA 91761

Ph 909 930 9980
Fax 909 923 3950

Just get the West Coast Fab carb hat and throw the ATI supplied unit away.
I predict that if you go 3 or 4 steps up in camshaft selection from my mild grind that you will easily make inexcess of 1,000 hp.

That red Challenger is one purdy Mopar!

Thomas

 

Norval, everyone agrees that the engine can easily top 1,000 hp. We maxed out on fuel flow and just started to go lean was why we shut it off at 5,800 rpm. If we had changed the regulator spring up from the installed 35 pound spring, perhaps another 2 degrees timing (it was at 30 degrees), and maybe made a jet change or two it would have been safe to fly. I have no intent of racing it at the 951 hp level, but it was fun to see what 116 octane fuel and ~ 7 psi more boost would do.

If I can even keep it from black tracking the strip at the 753 hp level I would be doing good!

Thomas

 

Steve, I'm done and will be installing it at the 753 hp level in my car.

When I picked up my engine today there was a marine 557 cube BBC with probably an F3 or F4 ProCharger and an air to water intercooler in the dyno room. I watched a dyno pull where it blasted off 1,190 hp and 1,058 tq with only 12.8 psi of boost.

Thomas

 

:eek: :eek: :cheers:

 

:D :cheers:

 

:eek: