Accusump - pros & cons

[1320racer]

………

[Robin Lawrence]

I laughed out loud when someone said that an Accuse is a “crutch” as if to question the abilities of the engine builder or racer to solve the low oil pressure issue during a run.

In some of the rules limiting classes such as Stock and Super Stock there is only so much one can do to mitigate the drop in oil pressure.

I am happy to see this post and the responses from those who have actually used an Accusump. I currently have my Ford Coyote on the engine dyno for some testing of various components.

My good friend Don West has a Stuska dyno in his garage. We park my engine there and get together to try different changes when our schedules align. One of the items that we have discussed is oil control, oil level and related results.

For you single cam racers I will explain the issues with the Ford Coyote engines.
Like all modern engines the oil pump is located in the front of the engine behind the timing chain gear and harmonic balancer. Our Mustang is a rear sump pan so the pump has to draw oil from the rear to the front of the engine.

In it’s stock configuration the Coyote has a VCT system that moves the cam positions to optimize emissions and low RPM performance. It uses oil pressure to move or “bump” the cams into a desired position that is specified in the OEM ECU. We eliminate and the VCT and lock the cams into position.

The Coyote also uses piston oil squirters to cool the pistons. We block those off.

The lifters are actually hydraulic pedestals as a pivot point for the roller followers that actuate the valves. There are 32 of those little bastards and they are fed through 4 separate lifter oil galleys. Lastly the cam tensioners are also driven by oil pressure.

On their high performance/RPM 4 valve engines Ford has recommended a 5-50 oil. Many Coyote engine builders recommend a 20-50 oil in the race Coyote engines. In my opinion there are several reasons to use a heaver oil.
With all the lifters and other items there is a lot of oil in the heads. These engines are 7 to 8 quarts with a stock pan. As the oil gets hotter and flows through the lifter galleys and cam tensioners it can get aerated. When that happens the lifter can collapse at hi RPM and flip the follower off the pedestal and valve. Most times it is the intake that drops between the exhaust cam below and causes the exhaust to hit the piston resulting in catastrophic engine failure. Ask me how I know.

After using a light oil on dyno several years ago I had a failure as described above.
Since that time I have run the heavier oils with no issues. I feel like I am giving up HP to run the heavier oils. Most high horsepower Coyote racers with wet sumps have solved low oil pressure issues by running 2 extra quarts.

Once the oil has left the pan and isn’t draining back quickly the over filling has resolved their issue. With turbos or blowers they can afford to give up a few HP with the resulting drag on the rotating assembly.

In 2023 I switched engine combinations. From a 2012 Rated at 325HP to a 2013 rated at 350HP.

When working on cam timing on the new combination I made the switch to a Jesel solid pedestal lifter. I wanted to try a lighter LAT 30R oil rather than the heaver oil I had used in my previous combination. The solid lifter pedestals will eliminate the chance of lifter collapse.

I run the narrower (than a Mustang GT) F150 oil pump. With the reduced oil requirements I don’t think that I needed the extra volume. Oil pressure at the filter is over 100 PSI most times.

Attached is a picture of the issue that I hope to solve with an Accusump. My Racepak shows that at 2nd gear my oil pressure drops to 36 pounds at 7400 RPM. As you can see it recovers in the later gears.
I believe there are several factors causing the pressure drop. The G forces from the launch and the oil climbing the rear of the oil pan and the amount of oil that has been pumped to the heads is slow to return to the pan and pickup.
On the chassis or engine dyno we do not see a loss in oil pressure. To further test this I have removed 1 quart of oil then another quart to see if the volume in the pan effects the pressure and horsepower. So far no pressure drop and no additional horsepower with 2 quarts removed. I will be removing another quart once we are back for more testing.

While in Michigan last weekend I visited with Coyote expert and engine builder Jimmy Ronzello. Jimmy helps me with my Coyote program and has a lot of experience with Stock and Super Stock Coyote engines.
I borrowed a couple of items for additional testing. One was another Ford oil pan that is promoted as reducing windage. He also has an Oil Filter Adapter from a F150 that has a computer controlled bypass that we might test. Ideally my goal here would to have between 70 and 80 PSI consistent on my runs with only 4 quarts in the pan LOL.
There are a lot of trade offs in these deals. I won’t be able to see results from an accusump until I am able to launch the car.

I appreciate the forum and being able to hear other experiences.

Robin

Robin

[Billy Nees]

Robin, thank you for taking the time to respond. I found it very informative! I may not be able to relate to it but still informative!

[1320racer]

Robin, I didn’t see any mention of coyote engines in the title of this thread nor in the OP’s opening post. Matter of fact he specifically stated his is an LS engine. More important, you offer no opinion about using an accusump pro or con in your lengthy post. Just saying

[Rory McNeil]

Originally Posted by 1320racer

Mcfly, it’s now the year 2024 and the vast majority of class racers and bracket racers have their engines built by professionals so you either ain’t got the coin or your arrogance eclipses your ego, seeking validation from a few old men like yourself wanting a merit badge for assembling your engines, setting a few clearances, assembling a few parts and torquing a few bolts who call that “building” their engines.

Well, at least I won`t need to ship my engine back to the "Big Name Profesional" if a spark plug wire falls off ! Or fly them if when the valves need adjusting.

[1320racer]

Your attempt at humor is as bad as your attempt at spelling Mcfly

[Rory McNeil]

Originally Posted by 1320racer

Robin, I didn’t see any mention of coyote engines in the title of this thread nor in the OP’s opening post. Matter of fact he specifically stated his is an LS engine. More important, you offer no opinion about using an accusump pro or con in your lengthy post. Just saying

I also didn`t see any mention of unlimited Big Block powered throttle stop dragsters , with no oil pan restrictions (by class), in the title of this thread, nor in the OP`s opening post. Yet, here you are!

[Race Clean]

You guys really need to stop argue with this guy,his only goal is to annoy people,he will eventually go to a new board and annoy others if he don't get any fights here.
He is just a Click-Bait

[1320racer]

So not only has Mcfly not replied to the OP’s question but now Mr.Clean too

[Bill Grubbs]

Originally Posted by 1320racer

So not only has Mcfly not replied to the OP’s question but now Mr.Clean too

Alright Biff…