Marks RX7 - lets break a rotary.

[andybond]

No. Not again!

 

[DaveL485]

Oh mate, not again!

 

[Mark Davis]

In the way of a quick update. Dented rear rotor again -I’m upgrading the fuel system - moving up to 1650cc primaries to match the secondaries and swapping out the fuel rails to a set of radium.

 

[andybond]

What part of the rotor dented @Mark Davis ? I am becoming quite the armchair expert on rotaries having watched more than my fair share of Rob Dahms videos now.

I know the difference between my irons , renesis and apex seals.

 

[Mark Davis]

What part of the rotor dented @Mark Davis ? I am becoming quite the armchair expert on rotaries having watched more than my fair share of Rob Dahms videos now.

I know the difference between my irons , renesis and apex seals.

View attachment 201939

Haha !

The rear rotor right at the top between apex and combustion chamber. Also two bent apex seals but not broken (they are designed that way as to not break up and grenade whole engine)

 

[Mark Davis]

Here is a pic

 

[andybond]

Haha !

The rear rotor right at the top between apex and combustion chamber. Also two bent apex seals but not broken (they are designed that way as to not break up and grenade whole engine)

Hmm. What caused that? At a guess heat? I cant see any oil marks where it got super hot though?

 

[Mark Davis]

Hmm. What caused that? At a guess heat? I cant see any oil marks where it got super hot though?

Detonation.

A combination of fuel pressure issues, faulty fuel pressure sensor and my KMS EGT box playing up.

 

[Mark Davis]

This guy is running 2bar on pump fuel. Using Syvecs with what looks to be a really good knock strategy which is not very common on rotaries. Listen to it!

 

[andybond]

Does sound well that. Mega money though Syvecs!

Water meth I note as well?

 

[Mark Davis]

Does sound well that. Mega money though Syvecs!

Water meth I note as well?

Yes I use water meth too.

 

[Mark Davis]

Not much to report, engine is being built.

I’ve invested in a back pressure sensor for turbo, will be mounted in exhaust housing.

I found this pretty interesting.

 

[andybond]

Far, far too many variables to support MRC findings here.

Its a single sample for start.

 

[Mark Davis]

Far, far too many variables to support MRC findings here.

Its a single sample for start.

I agree, I guess I had just never really considered fuel could be less octane than advertised. Not saying it’s happened in my case but interesting nonetheless.

 

[Steve Swan]

It would also be true to say that if you want Atom splitting power from your mega motor, buying fuel from the local petrol station may be variable to say the least. Would incorporating a knock sensor into the system to at least warn you, or to retard the timing, save a lot of money in the long run?? Det can be hard to hear on loopy motors until it is way too late to save them. I have followed this thread with great interest from an academic standpoint, I'm also glad it's not my money! I am completely fascinated by the amount of power it may actually make, but any small upset to it's requirements will result in total core meltdown. Are you within easy travelling distance of any UK distributor for either CARLESS HIPERFLO Think Demon Tweeks do 76 fuels and there is also Gulf . That would take the guess work out of the fuel and potentially not be much more expensive, could even be cheaper. Then you need the `Yak piss' map for the rest of the time.
I hope to see it truly make mental numbers (it was mental anyway) without hurting your pocket
Happy motoring

 

[Mark Davis]

It would also be true to say that if you want Atom splitting power from your mega motor, buying fuel from the local petrol station may be variable to say the least. Would incorporating a knock sensor into the system to at least warn you, or to retard the timing, save a lot of money in the long run?? Det can be hard to hear on loopy motors until it is way too late to save them. I have followed this thread with great interest from an academic standpoint, I'm also glad it's not my money! I am completely fascinated by the amount of power it may actually make, but any small upset to it's requirements will result in total core meltdown. Are you within easy travelling distance of any UK distributor for either CARLESS HIPERFLO Think Demon Tweeks do 76 fuels and there is also Gulf . That would take the guess work out of the fuel and potentially not be much more expensive, could even be cheaper. Then you need the `Yak piss' map for the rest of the time.
I hope to see it truly make mental numbers (it was mental anyway) without hurting your pocket
Happy motoring

Hi Steve,

It’s certainly been costly

Generally speaking tuners dont bother with knock on tuned rotaries as to your point inducing any knock in order to set parameters usually would end in engine failure, there’s very little room for error it seems. Having said that I’ve recently found a chap in Aus who has successfully managed to use knock control on syvecs. I do have a knock sensor plumbed in to my loom and could easily be switched on - I’ve been talking to the tuner about it.

Regarding fuels - I think mid to long term I will go down the E85 flex fuel route. It just means doubling injector, changing pumps and likely fuel lines too. From what I understand you tune on 95RON first and then tune on E85, the ECU uses the flex fuel sensor to sniff for octane and adjust timing/fuelling/boost accordingly. The downside to this is storing E85 somewhere, practically though with how I use the car this could work for me.

 

[Steve Swan]

One major problem with petrol is the aromatics which vanish with time lowering the values. That's why buying in sealed containers takes away the guesswork. Years back My mate would order 6, 117 litre drums of Carless 102 at a time, as this was the largest amount they delivered in one lorryload. At that time it worked out at about £1.30 a litre and super U from Tesco was about £1.20. He would phone around all the other shoestring racers when he was going to uncork a drum and we'd all assemble and fill our Jerrycans. He had a secure site and storage at the time, long ago when life was simpler and more fun...

 

[Mark Davis]

Hello my old friend, engine no 4 is ready.

This time I’m going to run lower boost, probably around 18psi. Keep it alive for a while - should still make 500.

Will start pushing it next year when I go down the flex fuel route.

 

[Steve Swan]

 

[DaveL485]