Been trying to find information on SSV and APV opening timing tuning for modified NA and boosted engines,

Can someone please enlighten me on the science and method for adjusting the port opening timing with Mazdaedit?

Thanks everyone

 

Have a look at the chart Racing beat did (on their website) showing slight improvements by altering those after a streetport . Any improvements will be barely noticeable but may as well get what you can.

For a boosted engine , there are some small gains by opening the APV a little earlier . These gains only exist because the valve takes time to open and when boosted , the engine is accelerating faster . So the aim is to get the valve open at the same rpm as a slower accelerating NA engine.

 

Hi Brett, how are you? Long time no speak, will catch up on Google sometime .

Is there any tuning possible on the SSV? And how does it work?

Thanks for the info above makes sense to me.

 

Hi ...carl ??
Yes , I have played with tuning the SSV quite a bit .Found small gains in spoolup to be had by opening it at 4000 vs stock range (3200-3800 approx.) . Not easy though , it makes tuning a nightmare , so I don't bother with it on any tunes i do for others. I did notice better fuel economy with it like that though .

 

Yes it's carl buddy,

What maps effect the SSV? Also for ported engines is there any gain to be had frpm VDI timings?

 

the SSV map ... just set all the values that are currently 0 to 4000 .

Yes small gains for VDI ... find that RB chart and you will see what you need to do .

 

It was the engine coolant temp vs rpm that was confusing me and couldn't quite figure out how it worked

 

lucky I figured it out for you .
It wont change anything unless the number you set is higher than the current opening rpm . And yes this took me ages to figure out
There is another map somewhere which isn't uncovered which is why the numbers are confusing.

Also : forgot to mention . If you dyno a boosted engine with APV settings to suit the road ............. you will get quite a power loss when it opens . This is because of the ramp rate on the dyno which doesn't match the acceleration of the engine on the street.

 

I have scratched my bald head regarding SSV operation and table. On paper, it looks straight forward, open at 3750. But it must be something more.

Would you care to explain briefly regarding this "temp vs SSV opening" table? I read it as its always open above 68°F coolant temperature in my original map(see pic). But started up, friend revved to 4000RPM, and could not see SSV opening or any movement, until I turned ignition off. Coolant should be more than 68°F. When ignition was turned off, it did a back and forward motion, so its not stuck at least. I understand it as this is a test procedure done by ECU every time its switched off.

FYI: When I use Virtual Dyno, neither can I see the dip in the 3750RPM area that you would expect. This makes me suspicious.

 

There is another table (load based) that takes over when engine is up to temp . Unfortunately we don't have access to that table .
The difference is too subtle for VD to pick it up ..... Disable SSV and you will plainly see the difference .
When free revving the ssv should open at around 3800 . 4000 on tach. might be slightly below that , try revving to 4500. (When under full WOT load it opens around 3200)

I wouldn't change SSV operation on an NA engine ... fwiw.

 

Aha, so there's another table!

As I have mentioned earlier, my 8 feels more powerful in low range, when cold. Did a log, and you can see that calculated load is higher when cold, something that indicates what I feel. Cannot see any difference in ignition timing. Intake temp is lower, but not enough to explain the difference,I believe:

 

Yes , denser air will yield more power............... 10degC makes a big difference.

 

any pointers to finding the racing beat chart mentioned above. Search of the site did not turn anything up.

 

http://www.racingbeat.com/RX8/Electronics/11309.html


http://www.racingbeat.com/manuals/11309dyno.pdf

 

Brettus, I do at the moment a rebuild with gtx3576r turbo setup. And I modded und ported my lower intake, too.
The VDI is blocked off with a aluminium core.
I will use the no longer needed vdi switch instead for the ssv. So I can change the map value of 7250rpm to 4000-4300 rpm or any other rpm for ssv valve.

 

not necessary ... you can change ssv rpm with the existing ssv map .....

Any pics of your turbo setup ?

 

too late... :D all these transitions from the vdi valve have bothered...Now the lower intake is a dream :D I also customized the ssv valve
Did you blocked off the vdi map value, too? The switching between the rotors do have for the turbo setup a disadvantage (turbulences)

 

I have tried VDI both ways , I actually thought I saw a benefit leaving it on when looking at Virtual dynos . But on an actual dyno , it would seem it does have more of a negative effect. So I turn it off now.

What did you do to the SSV ?

 

I will make a few fotos when the engine is in the rex installed, promised.
I did some terraforming customizing the chassi passenger side for the turbocharger housing... The charger it self is a customized t28 garret housing with gtx3576r internals, with ext. tial 44mm wastegate... The rx8 is too small for big turbo housings

 

I smoothed the passages, there were steps up to 2mm...really not good for flow...
The hole intake was so...

 

That might be the same housing i have (To4B) . I kinda wish i had gone with the gxt3576 instead of the 3582 ... just to optimise spoolup.

 

which rpm does your turbo spool up do you actual.... sorry for going total off topic

 

Full spoolup to 16psi by 3900 . It's actually pretty good , but could always be better.

 

Till which rpm is the boost hold?
Ok. Then would my calc not so bad. I think my turbo will full spool up @around 3500rpm.

 

All the way to redline . I have a 1.01 twin scroll turbine housing so may not be much of a comparison to what you have.