289/302-Wet or Dry sump Best?

[Jack Houpe]

I have a 3 quart accusump system, it is configured to open the solenoid valve when ignition is turned on and pre lube the engine, this works well, also I have the oil pressure light (idiot light) hooked to the accusump pressure switch which is set at 35 psi. I will say that when the light comes on at pressure dropping below 35 psi it would give you plenty of warning to do something, either pull over to turn the key off and drift to safety with no engine damage. No problems so far and I am glad I put it in. I am still leaning toward dry sump someday or remote mount oil pump. We are finishing up Mike Trustys MKII which has dry sump and the plumbing is very tight, this in my opinion is the only draw back besides expense. But how many guys have shelled a motor because of a distributor drive gear? What ever the choice, Accusump, dry sump, or external remote mount oil pump its better than replacing an engine. All of them is like trying to put 10 lbs of crap in a 5 lb sack, space is just not there.

 

[Ben]

Old forum, but what kind of HP increase would you see with a dry sump system?

 

[colin artus]

On a 302 probably about 20 to 25 bhp. Obviously depends as much on the 'before I drysumped it' state of the engine as the efficiency or otherwise of the new system. If the drysump can maintain crankcase vacuum the the power gain could be more. This is one of those proportional gains; the bigger the engine capacity, the bigger the parasitic and pumping losses in the engine, the more power to be gained back in reduced losses.

 

I built my 1st GTD with a wet sump engine, used in on the track many times never had a problem.
I built and Ultima GTR with wet sump engine, again no problems but as I was on track once a week and confidence and speed was growing I installed a dry sump 640 h.p. never had a problem.
Built a Ultima Can Am re installed the upgraded dry sump engine in this car, never had a problem.
Currently building a SGT 40 which will have a wet sump 450 HP plus and I dont anticipate any problems.
The cost of dry sump for my 40 was about another 3-4 k and space would be a problem, that's why I opted for wet sump
I think the choice is yours.
Although picture is a chevy lump it's dry sump and a plumbers nightmere.

 

[Chris Simpson]

I think a dry sump system is the ultimate solution but is it really necessary on a GT40. I wouldn't have thought a GT40, even on slicks, could generate enough G force in any direction to overcome the lubrication capabilities of a well designed wet sump system. Our Radical SR3 has a dry sump system, which has very complicated plumbing. However it has high downforce with all the bells and whistles like very low front splitter, side skirts, diffuser, 2 element rear wing, etc. and goes round corners at an astonishing speed - I find I can only drive it for about 15 minutes before my neck hurts from the sideways G but my son Tim can make it go very fast indeed. A GT40 is just not in the same league, as one would expect from a design originating in the mid '60s. The GT40 is just as much fun to drive on track however and doesn't hurt my neck, but I don't run it on slicks.

I am not sure how a dry sump system can give you extra power when there is an additional oil pump to drive, but it does have other advantages previously mentioned.

Chris

 

[roaldin]

:lol:

 

[Mike Drew]

I would reckon that a dry sump system is almost always 'better' than a wet sump, and almost never necessary or even noticeably beneficial. For a tiny sliver of the population, they are crucial, and for the vast majority, they are a complete waste of time, money and effort....

 

[Doug S.]

I am not sure how a dry sump system can give you extra power when there is an additional oil pump to drive, but it does have other advantages previously mentioned.
Chris

Chris, help me out here, please. I remember as a new forum member I posted a thread regarding dry-sumping, and the discussion led me to believe that the external pump replaced the distributor driven oil pump.

Here is a link: http://www.gt40s.com/forum/gt40-tec...ock-preparation-required-dry-sumping-sbf.html

Have I been floundering along all this time without fully understanding the system? Does the standard location oil pump remain functional in a dry-sump system?

Thanks for whatever help you can provide!

Cheers from Doug!!

 

[Frank Catt]

This is Keith Bakers first GTD which we have now converted to dry sump, with Gurney Weslake engine dynoed at 548 hp. Fairly simple set up works very well ! Frank

 

[Paul Thompson 'Hooligan']

Have I been floundering along all this time without fully understanding the system? Does the standard location oil pump remain functional in a dry-sump system?

Cheers from Doug!!

Hi Doug -

Nope - with a dry sump system, the drive to the pump is removed. It is a small hexagonal quill shaft from the bottom of the distributor, so removing the quill, removes drive to the pump.

For what it's worth, we used to monitor the oil pressure on Roy Smart's GTD40 and when using slicks were amazed at how the pressure fluctuated. Roy would replace shells every season and tried several sump designs. These fluctuations were not obvious on the mechanical capillary dash gauge BUT were very apparent on the electronic data logging. The dry sump arrangement on his later car alleviated the problem totally.

 

[Paul Thompson 'Hooligan']

This is Keith Bakers first GTD which we have now converted to dry sump, with Gurney Weslake engine dynoed at 548 hp. Fairly simple set up works very well ! Frank

Neat idea, shortening the tank and dropping it into the cill Frank...:thumbsup:

 

[Jac Mac]

Some early dry sump setups still used the OE pump as the pressure section, instead of having a pickup tube & screen the pickup was brought thru the side of the pan to the bottom of the oil tank, then a two or three section scavenge pump would be belt/chain or direct cam driven.

I would suggest that if your on slicks & using them to the limit a dry sump is a must have, Ive lost count of the number of cars that I have test driven & immediately noticed oil pressure movement in corners/braking that the owner/drivers claim never existed, that probably says more about their driving & visual abilties than anything else.

 

[colin artus]

'Some early dry sump setups still used the OE pump as the pressure section, instead of having a pickup tube & screen the pickup was brought thru the side of the pan to the bottom of the oil tank, then a two or three section scavenge pump would be belt/chain or direct cam driven'

Early Ferrari 308 is like this.

 

[Jack Houpe]

I have raced 3 open road races in April, one year I left the 5-20 Mobil one oil in my GT40 I use in the winter and noticed in hard cornering 110+ mph that the accusump light flickered till I came out of the corner and started going in a straight line, two thoughts were going through my head while I was trying to drive the race. 1 I wish I had a dry sump and 2 I will never run 5-20 in an open road race again. The next year I ran 15-50 Mobil one and the light never flickered but still wish I had a dry sump. The light comes on at 35 psi and the entire time I was in the long sweepers the light was blinking very quickly but the oil pressure never got below 35 psi and went back up to 50 in the straights. So if you plan on doing any aggressive driving and have the cash, dry sump is the answer.

 

[Chris Simpson]

Chris, help me out here, please. I remember as a new forum member I posted a thread regarding dry-sumping, and the discussion led me to believe that the external pump replaced the distributor driven oil pump.

Here is a link: http://www.gt40s.com/forum/gt40-tec...ock-preparation-required-dry-sumping-sbf.html

Have I been floundering along all this time without fully understanding the system? Does the standard location oil pump remain functional in a dry-sump system?

Thanks for whatever help you can provide!

Cheers from Doug!!

Hi Doug

I am not an expert on this subject but do know you need 2 separate pumping functions for a dry sump system - one to scavenge the oil from the sump and possibly other parts of the engine and return it to the oil tank and the other to pressurise and circulate the oil round the engine. My understanding is that the belt driven pumps used on American V8 engines perform both functions and are in effect 2 pumps in the one unit and therefore replace the standard pump. I would assume, therefore, that more engine power would be absorbed by this type of pump than the standard wet sump system pump. But I could be wrong!

A Formula Ford engine I raced with many years ago had 2 separate pumps on the same shaft driven off the camshaft as per the wet sump engine. I believe our Radical also has 2 separate pumps also.

Hope this helps.

Chris

 

[Andrew Komosa]

When I was a teenager, I rallied an Escort Mk1 which had a dry sump. Dry sump because I'd modified the oil pick up too short, so that when I went around a left hand corner fast(ish), the amber oil pressure warning light came on.. hence dry sump. This system didn't work for long as a conrod punched its way through the block on a cold winters day over the top of the Pennines. The wait for my dad and his tow rope was a long one. Hence, I don't believe dry sumps are a good thing!. Andrew

 

[Keith]

Hmm, Andrew, not too sure about your definition of a dry sump, but it was entertaining at least :laugh:

Anyone who goes racing without a rather large oil "idiot" light in front of them will never know what's going on. In the heat of battle, gauges are next to useless.

Oil temperature water temperature and oil pressure always had large coloured idiot lights in my cars, I didn't really need a tach either as I used the sound of the engine to shift.

 

[Dave Bilyk]

Andrew, interesting concept, a wet sump that transforms to a dry sump when going round corners. Clearly you had put insufficient development work into that one

Dave

 

[Jack Houpe]

When I was a teenager, I rallied an Escort Mk1 which had a dry sump. Dry sump because I'd modified the oil pick up too short, so that when I went around a left hand corner fast(ish), the amber oil pressure warning light came on.. hence dry sump. This system didn't work for long as a conrod punched its way through the block on a cold winters day over the top of the Pennines. The wait for my dad and his tow rope was a long one. Hence, I don't believe dry sumps are a good thing!. Andrew

:lol::lol: Good laugh for the day!