We don't do well with that question here... Many people assume that they will flow the same at 45psi boost pressure.

 

They flow enough to make 400whp ................

 

Brett changed his avatar! Noooooo!

 

32728 less ***** on the site

 

Since our fuel pressure is 60psi then that is the flow with 15psi boost

 

it's assumptions like that which result in boom-BOOM rather zoom-ZOOM ...


or you can confirm for yourself by sending a pump assembly in with a $60 testing fee to Deatschwerks ...

 

Fuel Pressure Explained - Injector Dynamics

 

Unless Deatschwerks can test injector flow against manifold pressure I don't think they will be helpful.

You can however use the flow vs pressure calculator with differential pressure and see how much differently the injectors will flow at 45psid vs 60psid.
Flow vs Pressure Calculator | Fuel Calculators | Resources | DeatschWerks
It just the square root of the pressure difference.

 

Anyhoo ..............

Update time :
Looking at my stripped engine has given me some valuable insight on where to take things from here . The engine did enough miles(25,000) and enough track days to at least provide give me some indication on whether what I'm currently doing is working .
Apart from the broken corner seals (and the damage caused by that) the condition of the inside of the engine is pristine. Virtually no carbon buildup and very little wear on either the side plates or the housings.
There is also no sign of any wear or overheating around the exhaust ports .
While i can't say for sure which of these things helped the most ............ it's the way I will continue to run my engine.

*Increase stock OMP calibration by 10% (stock setup - no Sohn)
*Run synthetic 5w40 with regular oil changes
*75/25 water/meth injection at around 350cc when over 10psi
*Limit rpm to 8200
*Increase oil pressure

The modification i did to the siamese sleeve earlier and again more recently (which saw track time) does not appear to have had any negative impact .
This has given me confidence to stick with another (slightly less aggressive) design . Not only will it flow more than stock but should lessen the likelihood of the divider falling to bits as it is prone to do.
I would really like to see if this design does anything for an NA ......... anyone willing to try it ?

The only other modification to this next engine, that wasn't on the last one .....will be solid corner seals .

 

Interesting choice of corner seals. I have heard of a Australian based builder using solid corner seals with some success.

However, long term performance results will be interesting.

 

Pre-mix as well?

I also have the OMP in stock configuration, no sohn (I'm assuming you bumped up the flow on mine as well) and I premix every tank. Although I'm nowhere near pushing the limits with the MSP I have been running a stock Greddy for 5 years and the engine starts and runs in all conditions as good as ever.

 

No premix . Stopped doing that years ago . And yes , I bumped your omp up same as mine

 

You talking about Renesis engines ?

 

I'm running atkins solid corner seals. I can't say much but I haven't had a problem yet. I'm kind of glad I did after hearing yours broke. But did you have to mill them for deeper apex seals?

 

I should explain this further .
There is nothing wrong with the stock rx8 corner seal design as it has a solid plug which prevents it from breaking when it gets squeezed by a rotor deforming detonation .
When you mill the rotors for rx7 apexs you need to also fit rx7 corner seals . It is a common thing to fit solid corner seals in the rx7 world due to the fact that the stock corner seals have a tendency to break as they only have a rubber core. My engine builder didn't seem to think it was going to be a problem on a Renesis ........ wrong .

Further to this , I hope you haven't got the Aitkens corner seals with the recess machined into them .............. they are known to cause premature wear on the irons.

 

Well that sucks, I figured the corner seal placement in the rotors was a little different and did not know the 7 corner seals would fit. I do have the recessed solid corner seals. That's a bit disappointing, but it happened before I got deep into the build. Oh well I don't put down enough miles to really be worried.

 

Make sure you up the omp rate !

 

I run 30% extra with 4 on the bottom end and 60 max

 

hmmm, how come you don't Pre-mix anymore? Have you talked about it in another thread somewhere? Obviously you aren't seeing any negative effects of no pre-mix but I'm just curious.

I typically don't pre-mix if i know I will be burning the majority of my tank on a highway trip.

 

I premixed on the last setup before this .......... ran omp at 50% of stock and premix at 200:1 thinking that ,as it would be using more oil (than stock omp settings) that way , it would be about right . That engine saw about 40000 miles but the side irons were really badly worn especially around the exhaust ports .
From that I reasoned that the premix i was doing (at 200:1 ) was largely ineffective. So I decided the best course of action would be to either up the premix ratio to 100:1 ish or just do away with it altogether and up the OMP .
I decided to try the later ........... i think it was the better choice !

 

Yes it is on the Renesis

 

Any clue when the damage happened? Before or after switching to the smaller housing?

 

Yeah .............. I know exactly when it happened .............. 2 years ago when i had the old turbo on here . As I mentioned on post 1 ................. engine was in need of a rebuild before i even started this project .

In hindsight ............... I think I should have done the rebuild first as I think it could have made a big difference to the spoolup issue that sent me looking every which way for a solution.

 

Ahh... Yeah that's a little bit more then freshening up the seals.

 

It is ............ but I was thinking the reason for the very low compression (less than 70psi on all chambers at 250rpm) was bent apex seals ......................which would have been just a freshen up if it were the case.