Rx8 turbo lagging help please!!
 

I just got my rx8 back together. i bought the car got a good deal because it wouldnt start. i had to replace the engine. the car had a greddy turbo kit on it. i put it all back together and it ran good for about a day the boost gauge was working and everything. Then yesterday the blow off valve was messing up found out the greddy type rd bov screw on to was stripped. fixed that but then today the turbo lags in 4th 5th and 6th sometimes in third it will build boost then lag. and help would be greatly appreciated. i am new to this rotary engine stuff and turbo stuff. Thanks in advance.

Do you know what modifications have been done to the set-up? What are you using for engine management?

i am using emanage from greddy and none that i know of stock greddy turbo kit with type rs blow-off valve.

the bov was making the whistle sound then the screw stripped and now it doesnt.

Sounds like you may be having a problem with the waste gate. Is your waste gate adjustable?

Type R BOVs are known to be a POS. Could be the BOV just leaking under boost but then again there could be all sorts of other gremlins loose starting with but not limited to the E-mangle.

Its greddys t618z turbo i do not know it the wastegate is adjustible

Also fix #2 where do i hook up the line? There is already a tap that is hooked to the boost gauge. Do you hook it to the emanage sensor hooked to the bov and intake?

Any chance you can post a video?
I'm not convinced from you description its lag you are experiencing

BTW .. get rid of the Emanage while you're at it

Don't forget if you have any leaks after the turbo on the intake side (that's were you want the waste gate signal, before the throttle body can be as close to the turbo as you want) and your loosing metered air the car will run pig rich and most of the boost will escape. Your boost gauge should be connected after the throttle body, to see the boost the engine is seeing. Re-check all your couplers then remove the BOV just to test to see if that was the problem (the stock kit has no BOV, it's a little harder on the turbo and stops it's momentum but it will be fine to diagnose) and I hope this goes without saying make sure theres a good seal where the BOV was, I would just put a peice of sylicone hose over the pipe and clamp both ends that way it's easily undone. How's your idle?? Any A/F gauges or readings?

Good luck!

Cheers

i have a video on the way and i dont have an a/f gauge yet the idle kinda wants to stall out sometimes but it saves itself.

Also make sure the oposite isn't happaning and your detonating from running lean it would sound like a bucket of bolts. Did the previous owner state why the engine blew? That sounds rich could be a leak, but definatly invest in a wideband A/F gauge. I would take is easy on her till you find the issue, also keep in mind the high gear higher speed pulls ask more from your fuel system. Get everything up to snuff to avoid changing the engine again. Any budget left over from doing the swap?

Yeah i have a little left over to spend and a the cel came on with p2070.

That's a intake tunning code, make sure the 2 vaccum line going from the upper intake to the lower intake valves are connected and that the acctuation functions properly and that the wiring harness at the back of the upper intake all 3 connections are pluged in. Budget wise, access port MazdaManiac (this also inludes him tuning it!) $600, coils BHR $550, A/f gauge $200, fuel gauge $100 + $65 for the BHR Aeromotive fuel line adapter, $100 upgraded fuel pump. If you can muster that it would help for sure!

it just threw p0301 code also. i checked all lines and connections where is this valve so i can check the operation and how do i check the operation?

Stop driving the car with a emanage o.O check all your plumbing.

You have one valve on the side close to the front of the motor and one in the middle under the upper intake manifold. This other code is not good it's a misfire, get a good rotary compression test done you may have to go to Mazda, cross your fingers you didn't blow this motor, and if you didn't you need the parts list I posted above before driving this car any further. Stay out of boost till you know.

why is emanage so bad? and how do you check proper operation

Make sure the arms move well and there's no un-linear resistance. But honestly this is the least of your worries at this point. E-manage is very basic, untunable, and generally unreliable, but it may not be the culprit. Did you swap the engine out yourself?

I am not sure the e-manage ever 'properly operates'

If you find your leak or stuck valve wherever, you are still in for lots of hurt until you get a better management setup

yes i did the engine swap and im not sure i have the greddy system hooked up correct but i have everything hooked up the way it came off. i just checked the valves and they are fine.

best i could do the clock spring broke so i have the steering wheel off.

Sounds like your BOV is leaking . To test this - try taking the BOV off and put a flattened soda can in to block off the hole then reattach the BOV .
You should not be running a VTA BOV with a MAF based tune anyway - but that is another story.

Yep I agree with Brettus on the BOV maybe being the problem, engine didn't sound like it was detonating (it's hard to tell with the wind noise), so hopefully the misfire code is from loading up the plugs, it's easy to pull the plugs and check.

I've got a VTA BOV and it works great, but it's a dual piston Forge that doesn't leak at idle it needs vacuum and positive pressure to open.

If everything is top shape with the BOV and intake side of things, maybe turn attention to the tuning, it be nice to see a data log of whats going on. Or possibly fuel pressure but this would be under hard acceleration and would recoup faster then what it seems to do (higher gear needs more fuel for the same RPM and throttle)


http://www.greddy.com/upload/file/03-RX8_TK_T618Z.pdf that's the link to the turbo installation if you want to double check e-management and other things

cheers

It may well do - but with any maf tuned engine , a VTA BOV is going to cause a big fuel dump into the engine at gear change . It's just whether you can live with that or not ......

I also VTA during my turbo days, it would dump fuel and bog the engine down if i stuck it in neutral down to idle. PITA during traffic jams but i lived with it for the sound. In hindsight recirc would be better, but not a deal breaker. I know it's pretty user to user dependent on how well the tune handles it.

Good advice
I don't believe the OP is smart enough to understand it

I drove mine VTA without drivability issues. :dunno: And at night I could look in my rearview and see the bright flash reflecting off the cars behind me......who always inexplicably backed off. :evil_laug

What would i use instead of a VTA BOV?

Recirc

Instead of VTA there is a hose that recirculates .... (THIS IS IMPORTANT KIDS PAY ATTENTION) the already metered air back to the intake "POST" Maf and "PRE" Turbo.

Ok so i tried the pop can method and nothing. I changed out the coil packs. No diffrence either. I did notice that if i press on the gas a little like half a centimeter the car will build boost through 3500 to 5000 no problems but its really slow and during that range if i push the pedel down it will bogg down and stutter. I checked the functions of the vlaves and nothing seems to be wrong. Still throwing p2070. Any thoughts? Im in western ny if anyone know a good turbo installer to look at this for me.

I don't think at this point that the BOV is the issue, it would be nice to see a data log, maybe invest in the access port right away then lots of people can help you by distance.

I've got the logs if you would like to see them Brettus, I'm not seeing any issue with my VTA setup, but someone with your experience may be able to point otherwise. My theory is went you close the throttle you close the throttle. Therefore the metered air is slightly irrelevant, and also if you recirculate the air then less air will be drawn in vs. if you VTA more air will be drawn through the MAF when the throttle re-opens. The only bad effect from a VTA setup is will idling or cruising under vaccum it will lean out if the BOV is not tuned properly, this is why I used a twin piston BOV. Simple to put this to rest all you need is a comperatives of 2 data logs.

Cheers

E https://www.youtube.com/watch?v=ofIK...e_gdata_player

These are my compression tests. Both front and rear rotors have the same compression.

That test is next to useless.

You need to have special compression tester that will capture each compression cycle and the RPM

Then you need to normalize the compression value

Yep this is right, keep in mind you have 3 different compression chambers per rotor therefore the pulses need to be read. There are specific rotary compression testers, mazda for sure has one.

Just for the sake of experimentation (and to be a boy for a while) - I set mine up VTA yesterday . Had to put a heap of tension on the spring to make it acceptable to drive .So much so ,that I'm now getting a small amount of compressor surge at low throttle .
Recirc is just way better from every point of view except the lack of a pssssssht noise.

Lol yep I love the pssssht noise, your experiment proved a regular BOV doesn't work efficiently, try a twin piston one: Forge Motorsport | Alloy Fabrication

That's what I have, works like a charm, can I send you a PM Brettus, I have something I did different on my Greddy install based on things you suggest and would appreciate your feedback but feel it wouldn't add anything to this thread.

The Synchronic with the anti-stall valve works well enough VTA ... but you still experience the fuel dump when it opens. Thee's no way around it in a MAF based system.

Perhaps I'll try it again one day now that I'm MAP based. Oddly enough, a couple weeks ago I experienced a coupler failure and it took me a good 10 minutes to even realize I'd lost boost...

https://www.rx8club.com/attachment.p...1&d=1348345486

Apparently there was still enough air traveling across the MAF to keep the ECU from throwing me into limp mode.

Any help?

If it isn't the BOV it could be a big boost leak somewhere else . Suggest you leak test the system - search " turbo leak test" on the net for how to do that.
p2070 is SSV stuck open which means................ the SSV is stuck open .... so fix it ;)

The SSV does a test cycle when you switch the engine off . Have a look at it while someone switches the engine off for you and see if it does this .

i thought the ssv valve did not matter because the block off plate and i asked about the greddy turbo. Fix #2 it says reroute the wastegate tube somewhere else where would that be? And would a bad tps sensor cause this problem?

The blockoff plate blocks the APV not the SSV, Greddy Fix #2 - you should move the wastegate signal boost source close to the compressor outlet most people put it in the cast elbow that attaches to the compressor housing.

Get rid of the E Manage it's complete crap and recirculate your BOV

What exactly are you calling lag? Traditionally lag is considered when it takes a long time for you turbo to spool, if you seeing boost in lower rpm's it not technically lag.

What rpm's is this occurring at?
What do your AFR's look like?

It occurs from 3500 to around 5000 rpm. And im not sure how to read those. My phone pulls the afr off both of the 02 sensors on the car. They are in a aa:bb:cc format how do i read those?

And i guess it studders and bogs down not lags. It does it to the point where it is going to stall out.

dude... you really do need some dedicated gauges too....

Fuel Pressure
Wideband O2
Vacuum/Boost
Oil Temperature
Oil Pressure

Pretty much required. I didn't notice but did you log AFRs yet?

I have boost and oil pressure. Waiting to get money for afr but my phone does for now.

You should be reading AFR's from the front O2 Sensor.

Read this:Air/Fuel Ratio tuning:Rich vs Lean | Turbobygarrett
That's a quick general explanation, those AFR's mentioned in that article do not apply to a boosted RX8 under WOT you should be seeing low 11's and cruising should be high 14's, there's a lot more to it than that though.

If you plan on keeping this car and expect it to last any length of time you seriously need to start doing some research regarding what's involved with owning a boosted car, getting everything setup properly and what you should be monitoring on a regular basis.

Like I said before, Ditch the E Manage, Get a Cobb Accessport and get it PROFESSIONALLY tuned and Recirculate the BOV, not doing this means you have air read by the MAF that's not making it to the Engine and you will get rich spikes.

Check all you coupler connections make sure they are tight to avoid boost leaks, and check all of your vacuum line routing, Jet Air, and OMP Lines

https://www.rx8club.com/major-horsep...uff-up-211884/