Idemitsu vs Redline for Rotary Engine

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AndyC

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Hi I have been running Redline 20w50 in my street/track-day RX-7 with a two rotor 13B rotary engine. This car is mainly driven to the track and driven hard, then back and garaged. I just rebuilt the engine and am thinking about switching to Idemitsu after the break-in. I have read that it is formulated more for rotary engines and that it was run in the Mazda race engines (I don't know if there was a special formula for them or the engines were designed around the oil).

So which do you think would be better: Redline which is a common and proven racing oil or Idemitsu which might be less advanced but designed for the rotary?

Does anyone have any data to compare the two?

Thanks,
Andy
 
The idumitsu has been around for a while and heard good things about i. I personally race an RX7 and use royal purple with good results.
 
http://www.idemitsu-usa.com/

Here's a link to the Idemitsu page describing their Wankel oils. Sounds like great stuff to me. 20w50 seems like a real waste in these small engines, though.

I don't know how well Redline works in a Mazda rotary, though. You could call their tech line and ask; they're very helpful. Let us know what you find out!
 
Yep Idemitsu seems great to me as well. 20w50 is recommended by all the good rotary shops, with a turbo I make over 500hp and 22psi of boost from a 1.3L engine.

I called Redline, they claim that it works well and I have liked it so far but am wondering if I can do better. I think I will give Idemitsu a call as well.

Thanks
Andy
 
If it is possible to do better than Redline in a high-performance application, the difference will be slight. Since the Idemitsu oil is formulated specifically for the Mazda rotary, it would be the best candidate to do so in that application. It will probably be more expensive, and will definitely be more difficult to find.
 
The Idemitsu actually isn't too expensive the Full Syn not a hydro cracked is alittle shy of 9 bucks a quart which is really cheap for a PAO Ester mix. Cheap insurance on that 13b if you ask me because building up one of those definitely aint cheap.
 
I'd go with the Idemistsu rotary oil as well.
RL 20W-50 is an incredably heavy oil with a HTHSV of 6.1cP; it makes the Castrol TWS 10W-60 look like a 20wt oil by comparison in service.
We don't know what the HTHSV is of the Idemitsu 20W-50, but it's KV100 spec' is lower and it has a somewhat higher VI so I'm sure it's lighter although still a very heavy oil.
Unless you're seeing extremely high oil temp's in the 300+F range or otherwise have low oil pressure I'd think the Idemitsu 10w30 would be a better choice or a blend of the two suit your hot OP requirements.
 
I will probably try to call around for people that have actually used Idemitsu in similar applications to mine, Redline 20w50 is commonly recommended by for my application because the rotary does run very high oil temps (half of the engines cooling is through oil) but I now have a pair of very large ducted oil coolers and the temps are much lower.
 
Originally Posted By: AndyC
I will probably try to call around for people that have actually used Idemitsu in similar applications to mine, Redline 20w50 is commonly recommended by for my application because the rotary does run very high oil temps (half of the engines cooling is through oil) but I now have a pair of very large ducted oil coolers and the temps are much lower.


Most engines are primarily cooled by oil. Think about it. The coolant passages don't flow to the pistons,the cam,pushrods(if equipped),bearings,oil does. Coolant dissipates heat from the heads and cylinder walls but oil does the majority of the cooling of an engine.
 
Originally Posted By: AndyC
I will probably try to call around for people that have actually used Idemitsu in similar applications to mine, Redline 20w50 is commonly recommended by for my application because the rotary does run very high oil temps (half of the engines cooling is through oil) but I now have a pair of very large ducted oil coolers and the temps are much lower.

The best practical way of optimizing the operational viscosity of the oil you're running is with your oil pressure gauge.
What is the optimum OP for your engine? At the very least you don't want to be running the engine at maximum rev's with the oil pump in by-pass mode; that would be counterproductive to say the least.
 
Originally Posted By: Clevy
Originally Posted By: AndyC
I will probably try to call around for people that have actually used Idemitsu in similar applications to mine, Redline 20w50 is commonly recommended by for my application because the rotary does run very high oil temps (half of the engines cooling is through oil) but I now have a pair of very large ducted oil coolers and the temps are much lower.


Most engines are primarily cooled by oil. Think about it. The coolant passages don't flow to the pistons,the cam,pushrods(if equipped),bearings,oil does. Coolant dissipates heat from the heads and cylinder walls but oil does the majority of the cooling of an engine.


A liquid cooled piston engine rejects maybe half the heat through the oil system that a rotary does, which is why most piston engines do not even have oil coolers. 1/3 of a rotary engine's heat rejection is done through the oil cooler. The heat load is massive.
 
Originally Posted By: DoubleWasp
Originally Posted By: Clevy
Originally Posted By: AndyC
I will probably try to call around for people that have actually used Idemitsu in similar applications to mine, Redline 20w50 is commonly recommended by for my application because the rotary does run very high oil temps (half of the engines cooling is through oil) but I now have a pair of very large ducted oil coolers and the temps are much lower.


Most engines are primarily cooled by oil. Think about it. The coolant passages don't flow to the pistons,the cam,pushrods(if equipped),bearings,oil does. Coolant dissipates heat from the heads and cylinder walls but oil does the majority of the cooling of an engine.


A liquid cooled piston engine rejects maybe half the heat through the oil system that a rotary does, which is why most piston engines do not even have oil coolers. 1/3 of a rotary engine's heat rejection is done through the oil cooler. The heat load is massive.


Interesting. Thank you.
 
I have a question.

Why is anyone using a synthetic in a Wankel? I've read (in the past) that anything other than suggested isn't good for it??

I don't know how much of that is true, but ppl have been following it for as long as I can remember.
 
Originally Posted By: PZR2874
I have a question.

Why is anyone using a synthetic in a Wankel? I've read (in the past) that anything other than suggested isn't good for it??

I don't know how much of that is true, but ppl have been following it for as long as I can remember.


There was a member here a while ago that wanted to trade some really high end oil for conventional gtx for his wankel. He said the gtx was the only oil that didn't get consumed at an insane rate.
Interesting to say the least.
 
I read about that and forgot the exact reasons why they said to avoid synthetics in rotarys. But it was an old Mazda recommendation. Anyway with modern synthetics they are better than dino for rotarys just the same as they are for pistons.
 
The rumour back in the 80s was that synthetic deposits were supposed to be "harder" than that left behind by mineral oils.
 
Always interesting.

Of note is the tidbit about the racing teams using synthetic on the track.

I would love to know the REAL story behind that. Someone please illuminate me...
 
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