getrdunn

iTrader: (7)

Question is not so much old vs new as some QFX etc still have the raised lip at the Venturi vs the hp style. Anyone ever do any back to back comparisons? I read an article that the earlier design with the raised lip at the Venturi was actually a better design and supposedly straightens the airflow. I'm looking for a couple 1150 or 1250's and thought I'd throw this out there as well as what most have had the best luck with.

For my 555/565 builds. Currently have 1050 hp style #8395 I believe but would like to be able to try a few on the dyno. Plan is to dyno one tunnel and one single plane. Carb in question is for single plane

Tks
John

getrdunn

iTrader: (7)

Example

ezstriper

can't answer about the dominators, but I do know the 4150 style the quick fuels are great units with tons of adjustibility that the older stuff just did not have, when working with 02's and seeing the AFR's at various RPM's is the stuff

BenPerfected

When are going to do your dyno work?

getrdunn

iTrader: (7)

This fall

Black Baja

iTrader: (2)

I've had the raised/ non raised go both ways with different motors. Carb on N/A motors are a funny thing you can build two identical motors and they end up wanting different carbs. I've seen back to back testing with identical carbs on the same motor and one carb make 20hp more. Dyno pulls were backed up as well. My philosophy with carb motors and Dyno sessions is take as many carbs as you can get your hands on and try everything. After you get that figured out and drop the motor in the boat then it's a whole different ball game. The Dyno will not simulate the same load that is on the motor in the boat. Unless you have already ran the motor in the boat and data logged vaccum readings at various rpm levels. At that point you could Dyno a motor load the engine to pull the same vaccum at the same Rpms and tune from there but it's still not 100% as it would be in the boat. Although much closer. One thing I've learned through trial and tribulation (mainly spending money) is you can have a screamer on the Dyno and end up with a pig once it's in the boat.

bck

Mine were on the dyno before with the smooth bore QF 1050s. When they go back on (maybe a few days) they will have brand new QF 1050 with the raised lip. I'm not expecting any difference, but we'll see.

getrdunn

iTrader: (7)

Ya it's perhaps a question not worthy of discussion however I thought I'd ck before snagging a couple used or new ones and sell what I don't end up with. Let me know bck how your new ones work out and what your running on when you can.

bck

I posted all those dyno sheets with the 4150/ 4500 a while ago. These are the same engines, just going back on with new carbs and Daytona boxes instead of the Crane. I was going to install all the accessories and marine exhaust as well, but now Im having second thoughts. Might just run them and be done.

getrdunn

iTrader: (7)

That's right. Tks for reminding me. I was thinking of that very thread earlier. Lot of good info.