When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
It would appear that my VDI or SSV valves are not functioning.
I did confirm that they are.
Dynoed the car the other day and you can see the results.
Tuner said that I am down 10% on my VE.
AEM intake and RB headers and no cats.
I did take apart the intake and cleaned the injectors.
So I could of connected something incorrectly the injector wiring looks ok
Maybe a loose spark plug wire.
Any thoughts?
What year? Mileage? How about a compression test (I only ask because somebody will)
I have a 2005 and when I dyno'd mine way back in the day (stock) I think it only did 180 or so (I need to try and find the dyno sheet to remember exactly)
Normally when the top end goes to **** like that its because of Ignition.
7K is also about the time the VDI opens as well so you might check that as well. (edit never mind just re-read your post and saw you checked the VDI)
I've also seen the screens in those AEM intakes get all sides and stuff you might want to recheck those.
Not sure what you were hoping for but just guessing with the mods and a tuner with a healthy engine ... 200+ hp would be reasonable.
2005 with 50k
new rebuild by Mazmart.
I removed the screens as I converted to MAP.
It was running great before I swapped over ecu's.
Like I mentioned above it maybe something I did when I took the intake apart to clean the injectors.
It would appear that the SSV opens before the VDI.
Is that right and would it cause that type of drop off?
Ahhhh cool. I haven’t seen any posts that I recall from someone using a MAP on a RX8.
The SSV definitely opens way before the VDI.
That said it isn’t a set RPM but a combination of Engine Load, RPM and Engine Temp, opens between 3250-5500 rpm
Ignition definitely possible. Think beyond the coils: spark plugs? gaps? ignition wires? dwell time? "small" things start to matter at high fire rates into a fast moving chamber.
I got all the spark plug wires to click when pushing on to the plugs except one.
That will be the first thing that I will check.
Maybe find someone with stronger fore arms
AFRs were fine
We even did a lean run to see if that helped.
I can post results of that if you like
Good to know SSV opens first
Got to be the one plug right.
Would a timing light show the problem?
A timing light would certainly help find a coil that's not firing, but a plug can fire but be too weak for good ignition or not be able to overcome the resistance through the gap as things heat up and speed up. See if you can get a proper spark tester where you can see the spark and confirm its thick bright and blue.
If one plug isn't on snug that could do it. Every air gap is added resistance. Check that both ends of the wires are well seated and the contacts haven't fatigued off (ask how I know)
I swapped out the spark plugs and is now performing better at top end.
The plugs I pulled out were 10.5's with very little mileage on them.
Street driving with pre mix may of done them in.
Off to the races with the new 9's!
Next stop is the dyno, again.
This time for an E85 tune.
Wonder what the optimal heat range spark plug would be for that?
E85 Dyno went better than the E0 dyno session.
Ethanol content was 77% and only saw about 15HP increase over previous dyno sessions.
Still looking for a restriction, maybe time to put on the straight pipe.
Only been running pump E85 (51%-83%) for a couple of weeks but the rotary seems to like it.
The Adaptronic ecu allows me to run E85 as it has additional inputs available for flex fuel applications.
I use Tuned by Shawn and like the tuning so far.
9 plugs are too hot for racing and sill crack the rotor housings around the sparkplug holes
there are ignition ignition issues if it won’t fire 10.5 plugs properly
and if I’m reading it correctly, it’s still only making around 190 whp?
I never saw this thread from when it was started, so just looking at the dyno graph in post #1 I’d suspect that the VDI is not opening, but that assumes the rpm opening point is still set around 7400 rpm. It could involve ignition too.
Ahhhh cool. I haven’t seen any posts that I recall from someone using a MAP on a RX8.
The SSV definitely opens way before the VDI.
That said it isn’t a set RPM but a combination of Engine Load, RPM and Engine Temp, opens between 3250-5500 rpm
it’s supposed to, but if the solenoid actuator vacuum hoses or the solenoid connectors get mixed up during installation and not installed on the correct intake valve actuator then obviously not, in addition to the whatever the specific rpm setpoints are set for each in the ecu software.
so there are several different ways to have issues with when the intake valves open.
.
The BMW HPDE at Summit Point Main was a blast last w/e.
I pulled the plugs at the end of the first day and found out that 2L was not firing.
Swapped out all the plugs and 2L appeared fouled at the end of the second day.
I put a timing light on 2L and it appeared to be eradicate.
Not real bad, but not consistent. Enough to give me hope.
Purchased a new coil (D585). Installed yesterday with fresh plugs and it pulls to redline hard.
Keeping my fingers crossed. Theory is a weak coil.
I could post photos of the plugs or vid of the timing light if there is any interest.
I thinks a dyno session would be worthwhile before I hit the track again.
My tuner Shawn adjusted the dwell for the D585s and it picked up power.
Thanks for asking.
I have a dyno session set up for next week.
Will post the results
Dyno session did not go well.
Had an obvious none working SSV.
This was NOT the case at the last session.
Ordered a new solenoid from Mazda comp. ($75)
I will test the operation of the SSV before I reinstall the UIM.
Use Eugene to command the valve open will applying a vacuum source.
It would be great that fixes it.
Thanks Doc.
I have heard of people heating them up with hair dyers etc before testing them.
I just got two new ones from Mazda comp and will swap out the VDI and the SSV solenoids.
Don't have an air pump.
Must of just failed between dyno sessions, as I watched the SSV actuate on the first dyno sessions.
I got charts to prove it.
So I am not going crazy.
lol
07-31-2021, 04:45 PM
