I drove about 500 miles the past few days down to south florida, my first time taking the 8 that far since I boosted. Noticed a few things..

1. At any cruising speed above 88mph (ironic?) My coolant light comes on. I don't have a gauge or a laptop, but the dash water temp gauge doesn't move. We've had alot of rain here this weekend, and even when it was in the low 70's from the rain, it would still happen. It goes away immediately once I slow down a bit. I really doubt the raidator isn't getting enough airflow, since if anything the added airflow from cruising at >90mph will outweigh the heat from the extra load. I had the AC on, and I'm not sure if it would do that same thing with it off. I think it may be my bottom bumper pan, as I noticed a few missing bolts on the back of it last time I was under there. I guess if air is getting out there, it's not going through the radiator/engine bay (not good).

2. Cruise control with the turbo is funny..the computer thinks its NA and gives it a good amount of gas to increase speed just a bit. Kinda cool to operate the BOV with the steering wheel controls lol.

3. I seem to have a big problem with the turbo surging. At 4-5K in 6th, the slightest increase in throttle leads to boost. And if I watch my gauge, it's all over the place jumping up to 8 or 9 psi (target is only 6!) and then down to 2. And of course the entire car surges forward. Makes casual passing and acceleration a pain in the ***. At WOT its much smoother...I may just need to work on the tune a bit at part-throttle

4. Seems like my most effecient speed is lower now. I used to get best mileage around 80 or 90, but now it's a bit lower...around 70. I did manage about 18mpg though (a personal best lol)

It held up alright though. I'm slowly building up my trip distances to the dragon (1400 miles round trip) so I can catch any problems here instead of there.

 

i bet ya i know what your problem is.... pm me

beers

 

The coolant light indicates your low on coolant, it doesn't reflect the temperature of the coolant.

 

I would have to agree about the coolant light. It is a level indicator in the
overflow bottle. Just put a bit more coolant in the overflow tank and it will go away.

 

x3

 

it's full (that was the first thing I checked)

could be a faulty sensor, but why would it only do this above 88mph?

i think my flux capacitor is putting too much load on the cooling system

 

Stop by my house I have a canscan thingie, if that will help.

 

The boost with cruise control is a little weird. It can waist a lot of gas, and get annoying, especially if you're going up hill.

 

add a little coolant. when ever some one reports their light on and i say "add coolant" they say "its full" and i say "add some any way"they come back later with " ok well the light is off now".

 

I am not yet to keen on the turbo rx8, but it doesn't sound like your getting turbo surge, it sounds like an issue with your wastegate under partial throttle, does your turbo have an internal wastegate, it may be sticking under partial throttle hence why your boost would jump around like that, not allowing the exhaust to bypass the the turbine and overboosting. turbo surge is when air goes back through turbo the wrong way going against the turbine, (would sound like a real annoying fluttering sound) this happens when bov sticks or when you don't have one.

 

that's compressor surge...different from "surging"

Surge is the situation when the compressor outputs more air than the engine can flow, which causes a backup of air at the intake and creates reverse-flowing pressure waves. This occurs when turbo or improperly sized for their application (like the greddy turbo is for the rx-8)

my wastegate may be sticking, as I'm having issues keeping the boost low..but I'm addressing that seperately

...and of course, I'll humor you guys and check my coolant level when i get home although swoope gave me an interesting point that I'm going to look into.

 

They refer to the same thing

Not exactly. Compressor surge is when the flow is insufficient to support the pressure.

Wastegates don't generally stick intermittently, at least I haven't ever heard of that happening. The part that usually fails is the diaphram. They are easy to test though. Just use a bicycle pump to manually actuate it.

 

I don't doubt that the turbo starts coming on boost very easily at that speed. You've got a lot of air going through it. Do you have an electronic boost controller? This should help with the surging and boost spike problem but it won't help you stay out of boost.

I've never heard of any car getting it's best mileage at over 80 mph. 55 seems to be about the magic number but no one likes to go that slow.

 

what's happening is the same, but the cause of the problem is completely different. This is happening at a static throttle position, and the BOV is not opening. There is no sound.

That is what I was getting at

I do have a boost controller...a profec B spec II. I might as well mention my other issue as well now, since it may be related.

I noticed a few weeks ago, that at some point in the no-so-distant past I had boosted to 13.5 psi. Target boost has been 9psi since I boosted (on HI mode anyway, 6psi on LO), and it had held that fairly well. Only time I had to touch the controller was on chilly nights, since it would boost up a little more (10.5 or 11 psi tops). I zeroed out the boost controller, and retuned it. All seemed well since I would go out on the highway at night and just run from 2500rpm in 5th all the way up. I found out later that those kind of "controlled" pulls aren't replicating the situation. It seems that if I'm in the RPM range of boost, but off throttle (as in a turn) quick application of moderate to heavy throttle will cause it to spike..and spike high. The profec seems helpless to stop it, even with a set gain of 1psi.

I know wategates don't intermittently stick, so I'm wondering if there's a problem with the profec solenoid. If it ever quits raining here, I'll go out and try and replicate the situation (it requires me to he in a high gear, at decent RPM with room to maneuver at who knows what level of boost) but with the profec off.

 

Not saying i'm right but I still say it has something to do with your wastegate, whether it's your actuator, or as you mentioned the boost solenoid, even just maybe a small very small leak between the actuator and the boost solenoid.

Your blowoff valve should only open when the throttle is closed, if it's not opening under a samll load then it needs adjusted.

 

I like the Profec-B. It's simple and it works. I do know one person who had to modify one though as it would fluctuate boost at certain points. I wish I knew how it was modded. It is currently installed in a friend's RX-7 but the person who did the mod to it (her husband) died of cancer a few years ago so I don't know what was done. It's got to be the wastegate or the boost controller. I can't think of anything else.

 

it's got to be the wastegate, or like stiffler said one of the lines between the compressor, the solenoid, and wastegate. I did some light pulls last night with the controller off and was hitting 8+ psi in only 3rd gear. AFAIK the wastegate rod has not been touched

I think due to the rapid onset of this problem, that I may have melted a small hole in one of my wastegate lines (and i could probably tell you the foolish night that it happened too). That is a hot part of the car after all. I've got some free time this friday before i drive down to Miami this weekend, so I'll diagnose for sure then. I'd love to be able to get back to worry free boosting again.

and hey, just for kicks...anyone care to share their profec (B or e-01) settings?

 

Just for kicks do you know anyone with a spare boost controller, or even maybe a manual one just to see if it's the solenoid, but def. inspect those lines carfully.
Let us know what you find out.

 

I visually checked all the lines, and everything seems copasetic.

I could bypass the wastegate solenoid altogether, but I don't think it would do much for me since I'm getting very inconsistent boost with the profec switched off. Only other route I could take is getting a boost leak checker and getting under the car to watch how the wastegate responds as pressure increases.

my profec settings are these:

set: 33%
gain: 5% (wont go any lower)
set gain: was 7psi, but lowering all the way down to 3 psi doesn't even fix it..only makes it slower to boost.

with the exception of set gain, the settings are as they have always been. I really need to get a laptop on the interceptor so I can show you all exactly how my boost is acting...it builds boost normally, and will hold for a brief moment at target boost between 3 and 6K rpm. Above that the response is very inconsistent. I can see why the boost would fall momentarily as the SDIAS ports open, but I can't see why it would spike up like that

 

Well looks like you guys were right..maybe

I topped off the water resivour and started running 100:1 premix before my 500mile trip to Miami and back. The whole way down I had no coolant lights even under 100+ cruise for over 10 minutes. Not sure which factor fixed the light problem, but I'm leaning towards adding water. The engine does run very nicely now with the premix.

My boost spikes seem to be less severe and I didn't feel any surging..then again, I was by myself this time, not with a moody woman who can't handle the speed, so "moderate" acceleration was almost nonexistent. It was pedal to the metal when it came time to pass. It still feels funny at light acceleration at high load (6th gear at >80mph). Not sure if I can tune that out or not. Maybe a different boost controller will fix it. Maybe i just need a larger turbo...we'll see.

One thing that worries me greatly is the pinging I occasionally get. I was "testing" with a new civic si, and it seemed like I had to give it more than I should have to get in front of him. That and the CEL began to flash. I didn't hear or feel any knock, so I think I may be right on the threshold of tripping the factory knock sensor. This of course was after 4 hours of highway driving in 95 degree, 100% humidity Miami heat..needless to say, the entire car was pretty heat soaked by that point.

...next investment: WBO2 sensor and a friggin laptop!

 

You no longer have a functioning knock sensor with the Intx.

 

flashing CEL = misfire, not detonation.

I'm not totally convinced that the factory knock sensor works anyway. Its still in effect with the eManage setup, but look at the number of people who have blown engines with that. Given that it doesn't seem to a) detect the knock in the first place, or b) retard the timing enough to stop the detonations, I'm not really concerned that the IntX doesn't retain it. The PCM might retard things enough for a NA car, but definitely not enough to stop the pinging on a FI car. I suppose if it is detecting the knock that you could use the IntX to retard as much as you wanted to, though. I guess I'm just not convinced that the sensor actually does a decent job at detecting the knocks in the first place.

 

The sensor works (to what degree, who knows), but the countermeasures do not. At least not as of yet.

Good to know that a flashing CEL is a misfire..We know the ignition system can and will fail at a certain point with boost, and I'm pretty sure I weakened my coils back in my canzoomer days. At least I feel a little better about my motor.

 

you might want to have a look at your coils....

beers

 

i need to..I have an ohm meter around here somewhere. Anyone know exactly what the process is to test them?

funny thing too...i *just* replaced the coilpacks in my truck. like 3 minutes ago lol