I just came across this post, since Craig Bloom did the dynoing, can I assume that you live in the Pacific Northwest?  What type of car and drivetrain are you using, and where will you be racing the car? I mostly race at Mission Raceway, but usually amke at least 1 race per year at Pacific near Seattle, Bremerton, and Woodburn Or. Be cool to see you and the car at the track sometime.

Hi Rory, Craig is a friend of mind and a skilled machinist. He has worked on my stuff for years. On top of that, he is an accomplished NHRA class racer which is probably how you know him. It's a small world. I live in the Portland, OR area so Woodburn is my home track. My car is a typical street/strip setup and not a dedicated race car. It's 69 Q code candy apple red Mach 1 with the above engine and a custom 4R70W trans. It's got a 31 spline 9 in with a new TracLok and 4.11 gears. The car isn't legal under 11.50 which is fine since the car probably won't do that given it's weight @ 3625lbs. I run 275/60-15 MT drag radials which is the best I can get under the stock wheel wells. The suspension isn't that special other than good shocks, delron shackels and Caltracs. For a street/strip car, it is a lot of fun which was really the only goal.

Will you be at any of the 2018 events at Woodburn?


-John



 

Do those numbers indicate a breathing problem? Wondering if 2.5” exhaust was a huge compromise

I recently put my 69 Mustang on a chassis dyno and lost 23% at the wheels as compared to a SuperFlow engine dyno. I had open headers on the engine dyno and full 3" Magnaflow exhaust on the chassis dyno. All I can say is that 2.5" exhaust will be more restrictive than 3" but it might not matter until an engine is over a certain HP. I have seen/heard many opinions on the benefit threshold from 2.5" to 3". Most say above 500hp. My personal thought is that your engine might put down a bit more HP with 3" but the installation hassle, drone, and extra decibels may not be worth it until 3" will provide a sizeable gain. By the way, my car is very LOUD even with full 3" exhaust. It would be quieter with 2.5"

Regarding drivetrain loss, I have automatic which probably doesn't help. Maybe it's no worse than the TKO600. Hard to know. I will always dyno the car at the same location so I can compare when I make changes.  The place I went to mostly does Toyota's so an FE set on kill was a new experience for them. Ha!

I was on a new DynoJet 424xLC. Just curious what brand you were on?

-John

Quote

I believe the Ford 2x4 is to blame. I am not aware of any common plenum in the 2x4 intake stream. All venturi's seem to be independent to each cylinder.

It's a dual plane intake.... doesn't work in the 1-4  5-8 dynamic, nor does each venturi feed one cylinder, two venturi per carb feed one plane.

I'd suspect it is an exhaust issue, or a sensor issue.

Thanks Drew. I wasn't sure how the dual plane ports work. I wish I would have figured out the port-to-plane-to-venturi correlation before I installed the intake.

How could it be a sensor or exhaust issue if the readings stay consistent across different headers and sensors? I respect the opinions on this forum given I am new to FE's but I can't understand how the sensors or exhaust could still be a factor.

Pretty much normal.  Open spacers will often smooth them out a bit side to side...

Thanks Barry. I don't have room to add an open spacer under the carbs, The Mach1 hood provides for very little clearance. Do you think a jet change on the venturi's that feed 5-8 would even out AFR's?

Hi folks, I have been doing some AFR testing on my stroker side-oiler with a Ford 2x4 MR intake and QuickFuel 4160 carbs. The jets are identical on all corners. The engine runs very well, but at WOT bank 1-4 is always 1pt leaner than bank 5-8. I have had three different headers on the engine without a significant AFR change so I don't think headers are the cause. I believe the Ford 2x4 is to blame. I am not aware of any common plenum in the 2x4 intake stream. All venturi's seem to be independent to each cylinder.

Do you agree that my 2x4 MR intake is likely to blame? I would like to equalize AFR's across all cylinders. To do this I could jet down the mains on the venturi's that serve bank 5-8.

I know I am chasing a small change but I see no harm in trying to make the engine more efficient.

Thoughts?

Thank you,
John

Quote from: jgkurz on September 20, 2017, 12:08:42 PM

Congrats on finishing Drag Week this year Doug! Maybe you already mentioned this, but how did your cooling system hold up this year? If I remember right, things got a little hot while stuck in traffic during last years Drag Week.

John, the only time my car has ever come close to overheating was last year during DW. It only happened in a half mile long traffic jam that didn't move for periods at a time. And I couldn't shut the car off because of my then hot starting issue. My cooling system does really well and never even hinted at getting hot this time around. It hit 190 at its highest, through a small town with busy traffic on a warm day of 87*. I have no doubt that an electric fan would cure any low speed or idling issues that would ever develop, but I never encounter them in my typical driving, and I like to keep the car as mechanically stock'ish' looking as I can. In fact, I want to ditch the aluminum pulleys (underdrive for the waterpump, BTW), paint the water pump and modify a Ford distributor, ditching the billet MSD, to keep it old-school looking.

That's great to hear Doug. I'm glad the cooling issue did not creep up again.

Congrats on finishing Drag Week this year Doug! Maybe you already mentioned this, but how did your cooling system hold up this year? If I remember right, things got a little hot while stuck in traffic during last years Drag Week.

BTW, David Freiburger couldn't get enough of your car. I think I heard two or three times on the Live Feed how he loved the Mickey Thomson look of your car.  So do I!

-John

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