1991 Acura circle track car

[Mrkemble]

Hello, I have a question that maybe someone here can help with.

My integra is used as a circle track race car. It's equipped with a 1.8 non vtec Ls engine. I am currently running 10-w30 mobil 1 synthetic oil and a purolator pure one filter.

This engine went through a complete rebuild about 250 laps ago on a 3/8ths and smaller tracks. We built it loose by honda specs in the bottom end, due to the high rev limit. I am turning a maximum of 8200 rpms.

Now when the engine is cold at idle (1100 rpms) it is producing 80 lbs of oil pressure. When getting ready to race it is about 180 degrees and producing about 35 pounds of oil pressure. But when pulling of the track at about 210 degrees the engine only makes about 15 pounds of oil pressure.

I was told that as long as it has over 10 pounds at idle that everything is fine. But going from 80 cold to 15 hot seems like a big gap.

I change the oil every 2 races and it looks pretty good when it comes out with just some light discoloration. Oil filters are pretty clean also after cutting them open.

Should I consider a different weight of oil or maybe another brand? Same goes for the filter is there something better?

Thanks in advance and I'm sorry for the novel.

Brian

 

[Mitch Alsup]

Insufficient information!

What kinds of oil pressure are you running when the car is fully hot and running near the top of the rev band?

The old (and general) rule of thumb is that you need 10PSI for every 1000 RPMs. So, 15 PSI at 1100 RPMs is just fine, while you still want 80-odd PSI at 8000 PRMs.

Is the 210dF number the oil temperature or the water temperature? If it is the water temperature, it tells you absolutely nothing about the oil itself.

I have a F355B Ferrari that sees a good deal of track use. Back when I was using 15W-50 oil it would come off the track with 285dF oil temps and idle at 18 PSI or so. Changing to 10W-40 oil (yes thinner) and it would run at 265dF on the track and idle at 25 PSI after a long hot run. Sometimes thicker is NOT better. But it all depends on the oil temp.

 

[Mrkemble]

during normal runs the oil pressure tops out around 65-70 pounds at operatin g temerature.

I have no idea actually what temp the oil is. 210 is the top of the water temperature range for this engine. Race water temperatures range from 180-210 depending on the conditions (air temp, and where I am in the pack of cars)

I guess I should put an oil temperature gauge in the car.

 

[Dominic]

That sounds like insufficient oil pressure in the top end to me. I would run some kind of a 40wt and see if it improves oil pressure in the top end. Perhaps do a UOA on one of the oil changes?

 

[Mitch Alsup]

OK, now we have some more info, but still not enough...

At what RPM does the engine first reach 65-70 PSI when the engine oil is good and hot?

If this is down near 3000 RPMs, then the 65-70 PSI is being limited by the pop-off vavle (and spring). You should be able to access the affected area of the pump and add a few thin shims to change the pressure at which the pop-off valve operates.

On the other hand, if this pressure is reached above 6000 RPMs, then you are likely flow limited out of the pump or flow limited by the oil galleys. In this case, on the next rebuild, you should enlarge thse galleys and insert a bigger iol pump. For the short term, a thicker oil will increase pressure at the expense of that oil flowing through the engine slower (not optimal at high RPMs but better than oil starvation).

 

[Dominic]

Mitch is right. I didn't even think about that.

 

[Mrkemble]

the oil galleries have all been cleaned up. The drains in the upper end have been enlarged and cleaned up also.

It Makes 65-70 psi of oil pressure at the top of the rpm range ( 7500+ ). The oil pump has a modified spring setup.

After the secong race I tried 10w 40 castrol syntec with a wix filter. At cold idle the engine was producing 95 pounds of oil pressure. this seemed high to me and immediatley went back to the mobil 1 10-30, and pure one filter. 80 psi at cold idle seems high also, but I have learned to deal with it. Thanks again for all the help.

 

[Dominic]

My *stock* 3.8L pushrod V6 runs 70psi at idle and 90-100psi at anything over 3000rpm, so 80 at idle is not necessarily high. It's definitely pushing its way through the bearings though and that's good.

As long as the flow is good and the pressure is solid, I think you're fine. If the oil temps start creeping past 220F though, you might want to consider 40wt.

 

[Mrkemble]

Ok for the next race I am going to run a pure one filter, with 10-40 oil and see what happens. I will just remind myself to let the engine get good and warm before I raise the prms. Thanks again for the help.

 

[Thermactor]

Try a different filter if you want to raise your oil pressure, like the premium plus. Almost as good filtration, much better flow.

 

[Mrkemble]

I don't neccesarily want to increase cold pressure. Plus as I should have listed earlier this car is ran on dirt and asphalt tracks. It is my understanding that the pureone's are a great filtering filter. What about running a 5w40 or 5w50 oil? This would help with the cold pressures, while keeping the oil heavier for the high rpms.

This engine is ran extremely hard for 20-30 minutes At a fast track that I run the rpms never drop below 6000 for 20 laps, this has to be torture on the oil I would think.

Again all you're help is highly welcomed.

 

[lindermant]

what about the HAMP oil filter for Honda/Acura?

http://www.inlinefour.com/honhamoilfil.html