Dual quads finished, sorta happy
 

First off... kudos to BarryR and Quickfuel for working through the all the "tweaking" problems. These are Barry's new custom TrickFuel 750s that come built and setup for stroked FEs (around 482" or there about).

I ran the car on the chassis dyno yesterday and was a little disappointed in the numbers but hey, nothing that a 300 shot progressive fogger system won't cure:eek::rolleyes: Seriously, I'm thinking about it..

The engine's a typical 600hp Pond based 482 that Keith builds with a hydraulic roller cam. The neat thing about it is that while having a wide-band AFR setup hooked up to an inside mounted welded bung it maintains between 12.8 to 13.0 AFR during all part throttle and cruise... perfect! On the rollers it made between 12.5 to 12.8 AFR .. amazing and perfect. This is as they came out of the box from QuickFuel. It looks like Barry has these nailed! If you're looking for dual quads on your stroked FE I heartily recommend these..

Dave

http://i140.photobucket.com/albums/r...alquads003.jpg
http://i140.photobucket.com/albums/r...bradyno093.jpg

Looks great.:cool:

That's some more to polish, where the choke??
 

undy Almost 600HP at the crank and you are CRYING:CRY::CRY: Here's a tissue.:o Gald the problem worked out. Hear the army has some JATO rockets you can mount in the trunk for straight line acceleration.:eek:%/:rolleyes: You need a vacation with warm water and cool drinks on the beach.;):MECOOL: Forget the NOS.:p You keep going and you will be flying with the angels.%/ 140 mph and you can have liftoff.:eek: Rick L. Ps get a breather mask and stop sniffing the R-134 freon. :LOL::LOL::):D

hmmmmm.... lift off at 140?????? I'll guess I'll need to target that number as my trap speed. Maybe just a 200 shot then??:eek::rolleyes::LOL:

BTW ..if you figure a 22% parasitic loss crank HP comes in a just over 600. The posted numbers are SAE corrected.

Dave, with your upgraded exhaust, I'd venture to say that the horsepower loss isn't that much.

I would say for the guys running the normal restrictive glass pack mufflers, that 22% is a good estimate.

Brent

exhaust isn't used as a criteria for DRIVE LINE loss----the exhaust factor is because of the exhaust and is the same whether engine dyno or chassis dyno

That's true that the drive train loss equation does not allow for exhaust, except that engine manufacturers typically use an "optimal", equal length header with minimal restriction mufflers while doing their dyno testing (not to mention electric water pumps, no alternator etc) and making their horsepower claims. The exhaust loss only helps to explain the excessive delta between fwhp and rwhp.

If I was to dyno an engine for someone I would use the exhaust headers/system that was to be run on the car------
For research about parts combinations several combinations of exhaust would be used looking for the best combination, same as for intakes and carbs, rocker ratios, etc

The drive line lost on a chassis dyno is just that, drive line !!

Jerry, put an engine on an engine dyno with good headers and exhaust, and then dyno it again with a set of Cobra headers and sidepipes. No, it's not driveline loss, but I see parasitic loss as anything that takes horsepower to use it.

If you take a fresh engine and put it in a car, then put it on a chassis dyno....what's going to be different? Driveline loss and full exhaust loss.

I agree with you 100%....I try to dyno engines with the headers that will be used on the car. Unfortunately, the way that dynos are laid out, a customer can't just run in with a set of mufflers and tailpipes and say that he/she wants it exactly how it will be in the car.

However, put a Cobra on a chassis dyno with a set of Cobra headers/sidepipes. I guarantee that they'll be more loss than if you were running normal full length headers and good mufflers. I would say that there would be a 4-6% difference. That's the 22% that I was referring to.

If you adjust the linkage on that second carb. to come in simultaniosly you will be pleasantly suprised.

My thanks go to David for taking the time and effort on getting the carbs sorted out and tested. He has been pretty much the "ideal customer" on these - insisting on getting a quality product and then offerring solid and documented feedback on how they performed at every step.

The secondary carb on this setup can be readily adapted to alternate linkage systems - note that the link pins are removeable and servicable.

Exhaust systems on a dyno
 

Jerry Clayton If you are running a motor on a dyno, 80% of the time it is long tube headers and a either an extension on the collector in the 20"-36" range for getting the best power from that motor. Most dyno cells I have seen don't have enough room to install a set of cobra side pipes. All cobra side pipe are different inside the muffler area. I have 2 sets, one for street with a 2 1/4" outlet before the turn out. They are quiet and kill the HP in my car. I also have a race set with a 3" inlet and outlet inside the muffler housing and there is a big differents. The honest way to check any exhaust system is with a back pressure gauge. WOT throttle at 500 rpms past your max HP numbers. Looking for 1.5 - 2.5 psi buildup for the best exhaust. The cobra is also limited with having a short transition between collector and side muffler. This helps HP but IMO hurts torque. I agree with you drive train loss and exhaust loss to some degree but there are some variables with testing on a engine dyno and chassic dyno. Biggest is the air in the shop. Have seen a 15 HP change between good and crappy air alone. We didnot take into account for wheel slippage on the rollers. New rollers on a dyno perfect readings, worn out dyno wheels and you get silly readings. Had this happen to me for not being able to get the rearend of the car tight enough on the roller to not slip under load. I smoked out a dyno chassic cell with this problem. Rick L.