loaner dyno headers
 

I just completed a freshen up and cam change on the 496. We will be at the Vrbancic bros. dyno (The Carb Shop) in Ontario this coming Wednesday the 8th.
The plan is to spend most of the time on the Doug's 1-7/8" headers that I run in the car, but I would like to try a 2" or larger primary on the engine to see what I may be loosing vs. the little street headers. George was not too sure if he had Pontiac round port headers at the shop, so I wanted to throw out some feelers and see if anyone locally had a set that was available to try?

Shoot me a response, a PM, or give me a call @ 805-714-0490.

Thanks!

I sold a set to a guy in Sonoma last year ???

Last time I was at Harry K dyno shop I saw a few header sets overthere.

Good luck with that Brian. If I can find the time I will try and stop by and say hello.

Thanls, I'll shoot him a message.

That would be great Ron, It's been awhile! We should be there all day.

not sure how much you're making. 1 7/8 should be good for up to 700 or so hp. please post the results.

I have a set of Hooker 68-72 GTO headers laying around. 2" primary with a 3 1/2 collector. They are dented up a bit, but should still work. Trouble is I'm all the way down in San Diego. Is anyone from my area heading up for your dyno runs that could grab them?

Yea, but I live in Las Vegas!!!!

Well, the cowboy math by weight, ET, and MPH indicates that I'm already at that level or just above. The cam change, while not a huge difference, should pick up another 20 or 30 if the plan comes together
The old cam is a Harold Brookshire solid roller(263/[email protected] 108lsa .650" net) that was ground for the old 421. I'be been using it for the past two years in the 496 and now that freshen up time is here and the car seems to be stuck in the 10.0x range, a proper cam for the bigger engine was most cost effective change to make. The new cam is also from Harold, and is 268/278 108lsa, .710" net, and a touch fatter at. 200" than the last one.
So, I don't really care what the HP value is, as long as long as the ET goes to single digits I'lll be happy.

Brian - My engine was on the dyno at Vrbancic Bros in 2007. At that time they had a set of 2" round port headers for a Pontiac. They had the sensor fittings in each individual tube.

Thanks Jim. George couldn't remember for sure. That will make things much easier.

Have some 2" Hookers with EGT fittings in every tube if you pay shipping.

Here they are.

Those will work. Close in design to what is on the car now, and not so much a set of dyno only "magic" headers that would never fit in the car.

Thanks to all that offered, and if anyone is in the area, please feel free to come by and visit. It should be a good day.

ooops - -forgot -- age is hell -

We made it down to Ontario yesterday afternoon and had time to get the engine mounted on a dyno cart. Hoping for an early start and a good day.

please post up your results...and good luck

OK, here is the quick rundown after a long day at the dyno. 35 pulls, 771 HP @ 6700 and 702 foot pounds @ 4700 on California 91 octane cat whiz.
The good cheater oxygenated VP 109 Ms gas netted 785/704.

Time to retire after a good bacon cheese burger and a half a dozen adult beverages!

Congrats! Excellent numbers! You should make another thread with all of the details.

ps. Our gas here is freaking horrible :(

Brian - How much did you have to jet up with the oxygenated fuel?

Hey Goat,
Very nice numbers for sure. Agree with R 70...start your own "How its done on cat whiz" thread. :-)
Looking forward to reading more about your hot rod. Thanks for posting

I'll post more details when I get back home from the trip. The combo has really just been years worth of sneaking up on the level of aggressiveness.
As far as the VP109ms fuel, we started with the same jet, and it made the best power. We tried changing the high speed bleeds from .031 to. 028 and it lost a few numbers.
The strange thing is that after we burned up the three gallons of VP (all we had) and went back to pump gas, the small amount of residual VP netted the same numbers as straight VP. A very slight blend might be a good cost effective performance boost.

More to come later.

Nice!

Yep. That's my plan with my car. Always mixing in some good fuel with the cat whiz :cool2:

Awesome engine. Looking forward to the details

Hello...
 

Hey Brian,

Good meeting you and watching some pulls. I hope that you make it to the Pontiac Heaven Event in Phoenix so I can see that big bad motor do some work :eek:.

If all goes well I might have my engine up there next week. I don't think I will make the power that you did, but it will be interesting to see the results.

Well, hopefully you can keep us posted on your results. I havn't done such a good job at that with the buisy dyno thrash and a house guest for the past ten days. Didn't make for much computer time.

Les, it was a plesasure meeting you as well. Thank you for coming by and hanging out with us.


So, the engine still sits on the cradle right where I unloaded it last Thursday. It's been go go go with everything around here, and getting back to work after a week off.
My only issue with the engine was that the oil pressure was falling off between 6000-7000 rpm. It did the same thing every pull. The pressure would climb very smoothly as the RPM was increasing, and then gradually fall off from 70 down to around 50psi at the end of the pull. It did the same thing pull after pull with the oil level enywhere from six to eight quarts in the pan.
I think that with the external oil pressure regulator dumping all if the excess oil back to the side of the pan, I created a bit of a flow restriction on the pick up tube side. We discussed that months back as well as the possibility of cavitation, and I am now going to build a larger pick up tube to see if that helps the matter.
It may be another week or two to get the engine back in the car to see how it works.

Here is a quick video of one of the pulls last Wednesday.
http://www.youtube.com/watch?v=Z3I0TVe-1XI

Did you ever post the details of your build?

James, I never did sit down and post it. It's something I wanted to do and it got away from me. There is really no magic going on, just years worth of sneaking up on the level of aggressiveness. I'm still even pretty conservative on compression, but there is no hint of detonation or pre ignition, so there must be room for a little more.

Here is the quick rundown:

IA2 block, 4.310" x 4.250", Scat forged crank, Carrillo 6.800" rods, CP pistons with full round 32cc dish that starts about .750" from the edge of the piston, and Total Seal AP steel conventional rings .043"-.043"- 3mm with a back cut napier second ring and 12 lbs. drag on oil ring package.

The heads are KRE high ports with 62 cc chambers and 2.200"/1.72" - 5/16" stem valves with T&D 1.6 shaft rockers. The quality of the chamber is why I wanted to run this particular head over anything ales avaialable at the time (late 2005). The pistons are on average about .002" below the deck and I use the Cometic .040" head gaskets.
It's just a combination of a good chamber, and piston shape that uses both quench pads to blow everything inwards at TDC and make for some good turbulance and a good burn.

The engine has a pretty heavily ported Victor intake, a Pro Systems 1100 Dominator, and little 1-7/8" Dougs headers.

Nothing too crazy, and I know I have some opportunities ahead with bigger headers and better oil control.

Wow your short block is almost exactly like my 496 was. You have a very impressive car considering the weight of it!! Bet the overdrive is nice to have on the highway
What is your timing? We found 28-29 worked best on my 496.

Mine was happeist at 31* total. Yes, I'm pretty well spoiled woth the OD trans!

How was your experience at Vrbancic Brothers Racing? Would you use them again? I'm looking for a dyno shop here in SoCal.

I used them twice, and I would use them again. You can commit to half a day (if that would be enough) if you can coordinate with someone else who wants to do the same.

Great guys. Been there once with mine and a few times with friends. These guys have a lot of experience in general and will give you whatever guidance you are willing to listen to.