Yeah, well here's my graph from the same model of hub dyno, ignore the numbers but look @ 6500krpm onwards right after the valve opens.



I'd guess it's either partially opening and sticking or the dip is mainly from the fuelling going tit's up as a result of it not moving at all. Like you say though, hard to tell from here, possibly could be a blocked injector but I would have though if they stuck the lambda probe in at the dyno they would have seen some issue either way?!

 

I'm going to try to test the movement of the actuators tonight, hope to find something

 

Just tested the SSV and VDI actuators, with the hose from the vacuum pump hooked up directly to them both actuators were fully open at ~-27kpa which appears to be dead on for spec. I also disconnected the hose from the intake manifold that leads to the vacuum chamber and put the vacuum pump on that and it held the -35kpa I pumped it to. After that I checked the check valve and it appeared to be working correctly.

In addition, I also verified that the cap I put on the nipple for the VFAD was secure, and it was.

Here is a datalog I did Monday night with the intention of getting it off to Jeff/MM on Tuesday morning

https://docs.google.com/spreadsheet/...XRPcDEweXQtcHc

On that 2nd/3rd gear pull I see that the calculated load was hitting over 100, vs the 90 that was logging while on the dyno

 

Good work!
Looking at this logs I do see what PhillipM was talking about with the APV.
Notice in the graphs that slow hump at the 6250 spot, but the max g/s value seems in line for most RX8's.

As far as the logs go, not bad, the afr's are a bit rich especially at the 7200 rpm and up, Jeff's in his webinar says he aims for 13.8 on NA motors.


It's been a long time since I've been in a NA RX8 but your second gear log took you 8 seconds to go from 2800 rpm to 9k? Is that long?





I requested some backup from the bored at work peeps.

 

It may be next week before I get any further with trying to track the issue down, but please keep suggestions coming, they help is very much appreciated.

Was planning to test a different spring set up this weekend, so I need to finish switching those, resetting the corner weights and alignment AND spend some time with the kids before Sunday.

One more thing I thought of this morning, is it possible that it could be an electrical issue? How critical is the battery when running at high rpm or is it running primarily off the alternator? I'm using an Odyssey PC680 battery mounted in the trunk via 4ga cable to the factory +battery connector. I thought the connections I had set up were sufficient (multiple ground connections in the trunk). Not sure if this could be an issue?

 

And finally another update...

Monitored the voltage on the way to today's autocross and it looked solid all the way to redline so that was ruled out.

When I got home and before the engine cooled down I checked the intake manifold vacuum at idle and saw it was running 50-52kPa, so a little on the low for the spec range of 56-66kPa.

I guess this week I'll be hunting down possible vacuum leaks and maybe have my co-driver come over and we can take a shot at getting a compression reading with a standard compression gauge.

 

U know using a standard compression tester isn't the best idea.

You need to get a reading from each face.

Otherwise you can remove the check valve from a standard compression tester and have someone watch the needle while the other cranks the motor

 

If you have a way of reading ODB2 live data, a vacuum leak will show (at idle) as a lower than normal MAF g/s (same amount of air being used by the engine, less passing the MAF), with STFT well off of zero

 

Best way is to take a video of the guage

 

Eeeewwwwwwwww yeah.
Nice one Brettus

 

I think the keyword there is normal.
I guess for our purposes here normal would be 5 g/s at idle.

But we know this isn't always the case.

 

I'll add it to the official ' Brettspeed Top tips' list

 

We need to get that list published!

 

/\ heh - well now that MM is a distant memory I might actually get away with it !

 

By "well off zero" do you mean + or -?

At idle it looks like ~5g/s on the MAF and the STFT is between -3 and -5%

 

Mine was negative, though I haven't understood why it is negative with a vacuum leak, seems to me like it should be positive.

If you have a vacuum leak, it's REALLY small. My normal MAF is 5.5g/s, with 0-1% STFT. With a small vacuum leak from the UIM/LIM sealing improperly, it changed to 4.5g/s with -8 to -12% STFT.

 

...and continuing updates...

Finally got around to testing compression last night. Total compression pressure was about 140psi for both rotors and with the pressure released the bounces were coming in consistently at about 100psi, so that all looked really good from what I can tell.

I guess at this point it's time to order up an intake gasket set from Mazda and go through that. I have seen reference to a TSB on cleaning carbon from the SSV (?), I haven't looked enough to see if the 2007's fall under that, so maybe that is a possibility? I have also wondered about the Racing Beat muffler that is on the car. It's the "Race" muffler and has a crazy bend (something like 100+ degrees) going into it, which dumps into a chamber, then exiting through a second chamber. The weld all the way around the inlet already broke once and had to be re-welded, I'm curious if something wacky is going on at high flow rates there?

 

Dyno'd at Rotary Performance on their DynoJet...

4th gear pulls on MM's 5th tune I believe (although I believe I have a buggy tune)

180hp, 130tq w/ all my mods... thinking something might be going amiss above 7.5K...

 

Rebuilt motor
Secondary bridge port
Extend port with opened up exhaust ports
Racing beat intake
2in header pipe with 2.75in collector
Single 3in no cats 1 muffler
Haltech interceptor ecu

220rwhp on dyno dynamics @ 9000rpm.

Sorry no dyno graph

 

Rebuilt engine
Street port (PPRE)
Rotors lightened and balanced
Racing Beat intake
Single race pipe with Extractors
Electric water pump
A/C removed
BHR ignition
Brettspeed tune Via Mazdaedit

242whp

 

Ppre?

 

Pulse Performance Race Engineering

 

Pic not working

 

Works for me ?

 

Works for me