This question is drag racing specific. How many out there don't run an oil cooler on there race cars? I have heard of some people not running them on strictly strip cars since they are only going 1/4mile at a time. This question is just informational and I do run an oil cooler I just want to know if there are those that don't and what are the benifits if any for not running one.

 

The only problem is, a lot of times in the final rounds, your class can run one run after another with no time for cooldown.



Plays hell with your dialin if you're bracket racing.

 

The rotor face temperature controls how much charge a NA engine can ingest on each cycle. Rotor temperature is almost completely dependant on oil temperature.



Compared to the rotor face, the irons and the rotor housing look cold to the incoming charge. When the incoming charge is exposed to the radient energy of coming off of the rotor it starts to expand dramaticaly. So the lower the rotor temp/oil temp, the bigger the volume of fuel air mixture inducted, and the more power you can make.



The rotary doesn't need to heat up to a specific temp before being run hard. If you have over 100 PSI and the oil is not too high in viscosity thats all there is. A piston engine needs a bit of heat so the pistons can arrive at the correct shape before being used hard. The cast steel rotor will not change shape much with heat. I think a big cooler is a must.



Lynn E. Hanover

 

The rotor face temperature controls how much charge a NA engine can ingest on each cycle. Rotor temperature is almost completely dependant on oil temperature.



Compared to the rotor face, the irons and the rotor housing look cold to the incoming charge. When the incoming charge is exposed to the radient energy of coming off of the rotor it starts to expand dramaticaly. So the lower the rotor temp/oil temp, the bigger the volume of fuel air mixture inducted, and the more power you can make.



The rotary doesn't need to heat up to a specific temp before being run hard. If you have over 100 PSI and the oil is not too high in viscosity thats all there is. A piston engine needs a bit of heat so the pistons can arrive at the correct shape before being used hard. The cast steel rotor will not change shape much with heat. I think a big cooler is a must.



Lynn E. Hanover

 

What oil cooler do you suggest and what do you use? I noticed that the factory mazda racing oil cooler, which Racing Beat sells, does not run a thermal bypass like the stock oil coolers do. Is there an advantage or disadvantage to this? And also is there a way to disable that thermal bypass on a stock oil cooler? The oil needs of my engine is one of my main concerns. I've read into a lot of your post on oil cooling mods and I am going to use them in my engine. I drag race unlike you who road races and I'm trying to build this motor as reliable as possible. Motor is a 13brew bridge ported, running a precision PT74GTS turbo, have LS1 corvette 80mm throttlebody adapted to the factory UIM which is ported and is a open plenum. I have a friend that had this same setup but motor was basically stock, the ports were just cleaned up, and he made 580rwhp @ 28psi boost on VP C16 fuel. He has since gone to methanol and a different combo so I have his old setup. And with that old setup he made over 200 passes without breaking down the motor. Hopefully with my motor combo I have right now I will be able to reach that same HP number under less boost. Well atleast that's what I'm hoping. Well let me stop running my mouth and any input from you is always appreciated. Oh yeah I'm putting this in a Datsun B110 1200 which right now weighs under 1700lbs.

 

I use three Setrabs. One in the pressure loop and two in series in the scavenge loop.



You could do a single big Setrab with a fan on one side and a washer pump spray nozzle on the other. Have the fan running nearly all of the time. and after each pass just idle the car with water spray on the cooler and the fan pulling air through it. That also means that you don't have to mount it with air coming from the grill opening. Unless this is a dailey driver.



Don't be dripping water when you go to the line. What trans will you run? I have a trick or two for stock transmissions.



Lynn E. Hanover

 

Yeah.. random dripping water is the MOST annoying thing to see.. ' is it fuel, condensation from something?' you never know





HOwever, im intreasted in your trick's for the stock transmissions if your willing to post em up here



-Jacob

 

I am intrested as well as my transmission is already apart awaiting a new 2nd gear synchro ring. I went to the mazda dealer expecting to pay ~15-20 bucks for just the ring and about fell over when he said 60 something..... Granted it a T2 transmission but jesus you can get a whole ring set for a NA trans for that! I wish I would have just got another used transmission.



I also have a question about your series run coolers on your scavage pump. I'm assuming there is a line running from the oil sump into one cooler then out of that cooler into the other cooler then to the pump? If this is the case have you ever measured the vacuum at the inlet of the scavage pump? I'm guessing it's real high with those two oil cooler in series before the inlet. I suppose it's mostly pumping foam though anyways?



Thanks for the info as always.

 

There are two scavenge pipes inside the engine. One is short and picks up oil in the front. The longer one picks up the rear.



Two lines take this oil and air mixture out through the front cover and into the suction side of two sections of the three section Peterson pump. The pressurized oil leaves the pump through a single outlet and then through the coolers end to end and then into the two Peterson in line filters in parallel, then into the tank.







When we ran the stock trans (it sucks) from the 1st gen RX-7 we found it hanging in gear with no way to get it out. This was the spring that expands to hold the three keys up. This spring has a 90 degree angle bent onto one end. In a fast shift the keys are depressed suddenly and the short piece of the spring breaks off. This allows the spring to rotate under the keys, until it gets out from under a key, and the spring on the other side of the hub still pushing up on that end, during the next shift that uncovers the unsupported end the key stands up in the groove and the slider cannot return to the neutral position. Thus the trans is locked in the last gear selected. The 90 degree bend at the end of the spring is to keep the spring from rotating out of position.



I took a broken spring and a dial caliper to the hobby shop and bought some music wire about the same diameter. I wound the spring around a big socket to produce a diameter about the same as the stock spring. I cut the spring so that when installed, the ends of the spring passed each other. I ground the ends in a long taper where the ends sat touching when installed. I spread the spring open so as to increase the tension. No matter what position the spring takes under the keys, it cannot escape and cause a problem. Made 4 of them and never had that problem again.



Also got a bit faster shifting from more force on the synchro.



The second tip is that hypoid oil has extreme pressure additives that make it good for differentials. Hypoid differentials strangely. The extreme pressure additives reduce the effectiveness of the synchro. The synchro has to bite through the oil film to grab the cone and spin it/slow it depending. A lubricant without extreme pressure additives lets the syncro work better, so faster shifts.

Some use just engine oil. Or engine oil and racing ATF mixed and so on. No cooler required for the street.



I have read about this trick, but I have have done it only to the Richmond Gear road race trans so far, but it works real well. Grind half of the splines out of the slider. You only have to grind the spline down far enough to mis the spline (depth)on the back of the gear. Grind half of the splines off of the gear. That makes a window about three times as big for the spline on the slider to hit the window on the gear. We use Redline trans oil designed for synchro trans use. Closer to how a dog ring trans works.



Longer synchro life, faster shifts, fewer missed shifts. Its all good.



We will (sadly) be leaving this house soon, and had a party to record that and other facts.

Many old friends from racing and old car restoring, airplane people and a bunch of computer geeks. (My wifes friends). I had a Lear fuselage lowered into the hole before we built the house. For variuos themes the pilot is dressed in different ways.



Note the Christmas lights and Santa hat on the pilot Bullwinkle Moose. And on the door of the plane is (What else) Frostbite Falls Airline.



Lynn E. Hanover

 

This is essentially how Liberty (used to) do it, although they would machine the whole splined section out of the face of the gear and press and weld in their own rings, which still looked for all the world like standard synchro splines with every other tooth gone.



I have a stack of them from old T-10 transmissions. I have them, because the splines are all worn to nubs and they kept popping out of gear. Just can't seem to throw anything away, even useless junk.