Awaiting patiently cause apparently Team knows what the fix is but is sworn to secrecy and can't tell us. But he did give me some solid advice and told me to ask someone else. Awesome thanks Team the team player.

 

Any idea where that info was coming from ?
What I have done is prettty radical and a little ................mickey mouse ... but very simple.
No point spilling the beans till I'm sure on it .
The aim for me was to have something that did the job down to when the yellow light comes on . It is looking prettty good for that goal.

 

Apparently dannobre holds the secret.

Anyways looking forward to seeing what you did to your pump assembly.

Keep up the good work.

 

Dannobre knows how to fix the problem............ but not using an in tank solution .

 

i'll be happy and delighted if i can go to 1/4 or below without issues. able to go until the yellow light comes on is a dream comes true...

Posted From RX8Club.com Android App

 

So I've learned a couple of things while messing with the fuel pump design .

1/Having a fuel pressure gauge (with an alarm) is .................prettty much essential when running this much boost!
2/The DW300 (possibly the Walbro as well ) flows too much fuel on the 2nd stage and as a result fuel pressure increases lower in the rpm range before tapering off later .I've seen as much as a 10psi dropoff. As a result of this , I have disconnected the 2nd stage altogether which has limited the variance to about 6psi.
3/The OEM fuel pressure regulator can vary . (3psi just between the two I've tried)
4/A combination of 2&3 means .....retune !




Messing around with this while running 16psi is frought with landmines !

 

Wow, landmines is right. That's a lot of variance, and scary.

 

https://www.rx8club.com/series-i-maj...orners-254079/

 

The line from the pump to the front of the car is obviously too small . We can get away with it via tuning but ideally it should be bigger as loagalinipoo suggested .
Also ..... we need to devise a better staging system for the pump.

 

Done

Ran the wire that used to run the vfad into the 2nd stage relay . Now can control second stage turn on rpm . In this way I have been able to retain the DW300 without the negatives that came with it .

 

Lol nice

Do you think it might be better running the bigger pump at low power or a smaller one staged?

 

I think running one not too big and not too small is the way to go ...
I would prefer to run the dw200 on our stock stageing setup given the choice .

 

One minor (i hope) drawback to controlling the pump via rpm vs the stock method .... at high rpm at full speed when you let off the throtttle the pump stays on full till the rpm drops .This leads to a pressure spike (up to 70psi ish) .

Edit : Fixed
Fitted a relay to utilise the stock fuel pump turn on along with the rpm switch . So now it switches to high speed mode after target rpm and about 80%load is reached . Turns off as soon as i let off the throttle .

 

Alternative solution might be to have a pressure switch that connects 2nd stage when you get above [for example] 3 psi? Its only when you have boost, that you need the extra fuel, right?

Some pages back in this thread;
You said that 57 trim might have been better left in there. Do you still have that opinion? How is throttle response when you are in an RPM high enough for boost?

Trying hard to educate myself, and to me TD06-20G looks like a good alternative if you are going to run 7-10psi, and not a race setup(low end grunt and good throttle response). There are several practical things that might stop this being a good alternative? TD06-20G is mentioned here as well in your older thread where you mention the point of restriction might improve power: https://www.rx8club.com/series-i-maj...r-flow-225716/ On top of that, we have the restrictions before compressor, that will make pressure drop to a bit lower than atmosphere at compressor inlet, also increasing PR slightly.

 

Effectively I have that exact same result with the wiring change i did above .






The more I learn the more I agree with myself ... LOL
There are pros and cons but the 57trim is the best compromise I believe . The 60-1 can outflow the turbine side and there are too many restrictions in the system to enable the 60-1 to shine anyway .I do sometimes enjoy the top end but do still miss the quick spooling the 57 trim provided.
That coupled with the fact that I am possibly the only person to ever run the Greddy/60-1 combo at the boost level that I do means that there are a lot of 60-1 owners out there that sacraficed the awesome spoolup of the stock Greddy but never got anymore gains than a 57 would have brought them .
Does that make sense ?

 

^I think so. You're saying that a lot of the 60-1 setups does not have any more to give than your old T04E-57 trim, but they lost transient response and low end torque to stock Greddy and 57trim. Correct?

Did not understand how you were able to use load as a criteria for running 2nd stage..? Schematic/drawing is always nice. And one thing; I'd recommend to use a solid state relay if possible. This is less prone to bad contacts - since there are none

 

Well ,the thing is , nobody else is runnig 15-16psi on a greddy 60-1 . The reasons for that are many and varied but my point is ............. if you aren't going to run 15 psi ............what was the point in having the 60-1 when you lose out in spool up and gain ..................nothing ?


I used the stock control circuit but interupted it so it couldn't activate under 6000rpm. The stock circuit is load/rpm based . At 6000 rpm it needs about 70% load to switch on which is just under WOT in an NA car.

 

Ah, I did not know that stage2 of fuel pump had load as an criteria for being activated stock.

I remember you saying writing that the GT3071 would be "All the turbo you needed in a RX8", cannot see when or where you went away from this? Any good reason for this?

 

I might have said the GTX 3071 or the 3076 was the best all round street turbo but certainly not the GT3071 ........ The 3071 is about the same output as a To4e 57 trim but both are on the small side of ideal .

The 60-1 wheel size is actually better still .... but my experience is that the 60-1 is ,in effect ,too big for the greddy turbine/turbine housing .

 

My memory must have masked out that "X".

I have been roaming around, I do not know if you've seen this page: FC3S Pro v2.0:&nbsp Turbo Tech - Compressor Maps

T04B H orh V-trim seems like an interesting option as well?

 

Yes both of those look good ......have you tried to see if you can get one ?

 

Had great day doing some dyno tuning of a couple of rx8 NA race cars . Learn't a whole heap and clarified a few things in my mind about NA tuning . At the end of the day the owner asked if I wanted to throw mine on .
So this dyno was done on a dyno dynamics dyno . I have turned back the boost a little since my last dyno (13 psi at peak power) and am running more water/meth . The unfinished pull was without W/M . The guy didn't finish the pull because it was looking a little lean ...... shame as would like to have seen if i was losing anything up top.



They f'd up the rpm - rev limit is set at 8500

 

Still a damn nice number to see!

 

Thanks ... Best part is that the whole setup is not on the edge like it seemed to be at higher boost .

I had to drive about 400kms to get to the town where the dyno was and much of that was on the boost through some really nice windy roads - yummy !

 

good numbers. What's your timing look like at that boost level?