Marks RX7 - lets break a rotary.

[Adey]

come on @Mark Davis post it, you know you want too, also where did you do it?

 

[Mark Davis]

Oh go on then !! To be honest @Adey I’m not happy yet, I think I can do better.

First run at Dragy today, awesome app, really cool to be able to get real world performance on the fly, a good barometer for future improvements.

I managed 3-4 runs in busy day time traffic on the A40 towards Oxford, I was trying to figure out the best gear combination. In the end this run was all in 3rd as 8400 limiter is around 103mph. I think I can do a 2nd to 3rd shift holding in the power band moving from 2nd to 3rd to shave a few tenths off.

As the car was over boosting to 25psi after mapping the tuner has pulled the duty cycle down a few % so it’s safe for the road, boost is around 18/19psi so I’d guess under 600hp at the mo.

 

[Mark Davis]

A few modern cars as a comparison and Adey told me earlier the 2019 Porsche GT3RS is around 3.8 60-100 so it’s not shy.

 

[Mark Davis]

@Adey bloody Dragy only had enough charge for one run today, typical ! My fault for not checking charge. I did shave a tenth off in that run though, I think it has a 3.7 in it before I wind up the boost.

 

[Adey]

epic fast! super flat road too, where was this one....? I really struggle to find place to do a pull

 

[Mark Davis]

epic fast! super flat road too, where was this one....? I really struggle to find place to do a pull

Was the A road that you take before you turn off to the Green Dragon pub, A435 is it ?

Cirencester bypass (A419/417) is a good place. Has plenty of lay-bys if you need to stop.

 

[Mark Davis]

Little Go Pro test last night, trying to figure out best place to locate it in the car.

Too hot for any timings last night using Dragy but nice to stretch its legs for a bit.

 

[Adey]

didnt fancy giving chase to the bikes then

 

[Mark Davis]

didnt fancy giving chase to the bikes then

Haha no I was trying to figure out what my boost was doing.

 

[andybond]

I hear braps, I press like ...

 

[Mark Davis]

Hello everyone. Just checking in to let you know I’ve damaged my engine. Pulling it today for inspection.

Loving life

 

[DaveL485]

Whats happened to it now?!

 

[Mark Davis]

Unsure yet Dave, tuner is going through the logs. Engine is out and off to engine builder tomorrow.

 

[Mark Davis]

I’m getting good at this.

 

[Duncan Grier]

Sad to see out so soon after all the hard work

 

[DaveL485]

This is a strangely familiar story.

Almost Deja Vu?!

 

[Mark Davis]

It is chaps but not much I can do but make it better next time.

 

[Mark Davis]

Whilst my engine is away getting fixed I’ve sent one of my HX50s off to be rebuilt with a slightly larger compressor wheel of 76mm compared to the current 67mm, keen to see how this changes things.

I would expect a little reduction in spool but should flow much better overall. Not too concerned as despite the HX50 being rather beefy as it is the log has shown it can hit 24psi by 4300rpm. I’d give up a bit of spool for additional top end flow.

 

[Mark Davis]

Unsure yet Dave, tuner is going through the logs. Engine is out and off to engine builder tomorrow.

We have a theory now after looking at logs.

For some reason likely just down to the difference between the load on rollers vs road the car hit 24 psi at 4300rpm which considering the car was turned down to 19psi was a decent boost spike. Now even though when it hit 24psi AFRs were fine at 10.5 there was a small window where it could been considered too lean coming up on boost around 14/15 briefly.

As I run Goopy apex seals they don’t shatter or break, they tend to bend which would explain the low compression on the rear rotor. The benefit of this means you don’t tend to wreck the plates and housings meaning it could just result in a fresh set of Goopy seals and we are good to go.

What we can yet explain is why coolant is pushing through the long bolts. I’m hoping this is just a sealing issue rather my bridge port breaking leaving a big hole in my coolant seals. I don’t think the latter is the case as coolant temps were perfect.

 

[andybond]

There really is only one solution. Bolt another iron and rotor on.