Who's dyno is that? Cobbs?
Who's dyno is that? Cobbs?
Golden's car is a well sorted out vehicle, & very meticulously thought out for the products chosen...VERY NICE CAR!!!
Thank you very much!!!
Evo8John posted this on a different forum:
Well, I just listened to the video's a few times and I can't figure out what it is.Originally Posted by evo8john
I think it's one of:
1: Compressor surge
I was getting compressor surge before the tune because I was going a little too aggressive with my MIVEC tables to get the spool at a very low RPM.
2: BOV leak
It's happening right at peak boost, so the BOV may be fluttering / leaking. Which could be why my peak torque numbers were down about 25 ft/lbs from where it should have been.
3: Boost leak
Related to #2, but from a different place.
4: Aliens Zapping my car with their stutter g-g-g-un.
If anyone has any ideas of what it might be, please post up. It happens in all 3 videos. Same noise and same pattern.
(I know Biggie will have an opinion. )
Id say it's #4.
It's hard to say. Have you done a boost leak test?
No I haven't. I don't own an air compressor, or a tester.
Though, if a boost leak is there, I was tuned for it. :-) So fixing the boost leak will cause it to go lean.
All of the EVO X'S I have been in sound like that,so I don't think you have a problem.
huh......that makes sense.
Try to stay with me on this, it's a bit scatter brained, but sometimes things don't happen in straight line.
I was messing around with my BOV today. Chad tuned me to 26 something PSI. Almost 27. Lets say it was 26.75 for those who like exact numbers. Then evo8john pointed out that there is a flutter sound during spool in all of my videos of the X on the dyno. I don't currently own an air compressor, so a leak test can't be done, though I've been meaning to swing by Lowes to check out prices. Then Street Concepts goes and has a sale on the Synchronic BOV. So I start looking into this and other BOV's. Synapse has a hand full of youtube videos out there. I was watching one of them, and the guy (BOV designer I believe) was talking about increasing fuel economy at partial loads by leaving the BOV open during vacuum conditions.
Let me explain. All of this explanation assumes you have a recirc BOV. During partial throttle loads, a turbo charged car still runs with vacuum in the manifold because the turbo is not spooled. If the BOV is closed during a vacuum condition, (which it is stock) then the air has to flow through the turbo housing, where the turbine is not really pushing air. This is restrictive to the air flow, so the engine has to work harder to suck air, and the turbo heats up the air charge. Then the air flows through the intercooler and finally into the throttle body. If the BOV is open during a vacuum condition the engine will suck air from directly behind the MAF sensor, through the BOV and directly into the throttle body. Some air will still travel through the turbo and IC, but most will take the shorter less restrictive route. Basically we are using the BOV to allow our car to breath like a true N/A engine during partial loads. And I am looking to get N/A mileage out of my 2.0 L engine.
Ok, back to my story. This morning I hooked up my Forge BOV to the vacuum line that goes to my stock BOV. The Forge BOV stayed wide open at idle. My AP shows -8 psi during idle. While driving, the lowest the AP ever shows is -10 psi. So, I swapped them to see what the stock does. (I need to plug the holes or the car won't run.) The stock BOV stayed shut during idle. If I revved the engine, the stock BOV would crack open a hair. Not enough to help with part throttle load. I tested the valve / spring pressure of both with my thumb, and the stock BOV was stiffer, even with the Forge adjusted at it's hardest setting. So I fully hooked up the Forge BOV and took her for a drive.
First thing I noticed was after spooling the turbo and letting off gas, I could hear the turbine spin down. I believe this is now audible due to the air now flowing through the BOV instead of the turbine, which whould help to slow it down and silence the whine. I had to reset my fuel mileage gauge because I had the car idling for a while. See, for some reason, the MPG gauge resets if the car has been off for 3 hours. There is a manual mode that doesn't reset it... but get this, when you turn the car off and back on, it goes back to auto mode. Lame lame lame. Someone needs to slap someone at Mitsu. Ok, rant over. So I noticed that my mpg was higher than I normally see while cruising around my neighbor hood. More on mpg later. I drove out to the highway and made a couple of data log runs. It seems that I am now boosting to 29 psi. Yes thats 2 psi more than Chad tuned me to. I think the flutter sound in my dyno video was the BOV leaking. I was actually thinking that the Forge BOV wouldn't be able to hold boost due to it having a softer piston feel. But beings that boost is on the vacuum hose, and it doesn't have a boost reference to the back side of the diaphragm like the stock BOV, I think the diaphragm is forcing the valve shut during high boost conditions. This is the same reason why the stock one leaks, due to not having boost help hold it shut.
I left the Forge on while we drove around today. I noticed my mileage went from around 16 in town to around 19. Granted, one day of a little driving is not enough to see if it has really made any difference, but it does mean that it didn't seem to hurt anything. I will keep it on for a while to see what actually happens with my mileage.
So I'm pretty sure the stock BOV was leaking / not fully shutting during spool. This is probably why Steve got such higher numbers than I did on MKC's dyno. I guess he ended up changing his BOV before they were done tuning. The sad thing is that I had my Forge BOV with me, but I didn't think of swapping it. And with the stock BOV holding as good as it was, Chad didn't see any reason to swap either. (i.e. there was no indication that it could be leaking)
I've read about a lot of guys complaining about partial throttle modulation with the Forge BOV. But as always, some guys swear by them. I guess time will tell what I think. I really like the design of the Synchronic BOV and the Perrin BOV.
Here is a link to the Forge BOV I have:
I'm not sure which Forge BOV guys usually run on the X. I am running this one in full recirc. If it was vented at all, the intake would suck unfiltered air through it. Very bad.
Last edited by Golden; 02-28-2010 at 03:47 PM.
Be sure to keep monitoring your mileage and report back (I'm sure you will). I'm intrigued.
I found an image laying around of the ECU boost control (drain type system) of a turbo charged vehicle. In fact, I think its from the Evo X. Anyway, a few minutes in gimp and here is what we have:
Bov Closed - Normal intake path (green)
Part throttle Vacuum condition with the BOV open - Intake Path (green)
...for those of you that need visual aids.
I am runnig the forge bov in recirc. and I love it also i,m getting about 22 -24 mpg at 24.5 psi.
Aerodynamics for the X
Here is a Mitsubishi Technical Review on the Aero Package designed for the Evo X. It shows why the wing was designed with different angles and how the Evo X wing has around 1/3 the drag of the 8/9 wing but ends up with more down force (10% or so increase)
p.s. After reading, you will realized why vortex generators are not a good thing on the X.
Gas mileage update:
Twice now I've done a bunch of errand running around town, all 40 mph and less, and I'm seeing right at 20 mpg. I was not babying it either, both times I hit full throttle at least twice. This is huge because I used to see 16-17 mpg before I tuned for mileage and the new BOV. The sticker on the side of the car said 17/22 and I'm now seeing 20/25 (and highway mileage may have gone up more since my BOV).
I will post more on mileage as it's consumed.
Side Markers Tinted:
VHT Nite Shade - Spray tint in a can
Push toward the thick end and the front pops out.
Here is the hole left behind:
There are words all over these guys, so I sanded them off. In this picture, I lightly scuffed it so that the raised lettering could be seen by the camera. If I didn't sand the letters off, they would look like crap because the tint would pile up in words and look silly.
All sanded down:
Ready for tint. I cut holes in the box to keep them in place, standing up, and slightly raised. It worked great.
First coat of tint. They looked really nice after this one coat. If I had a Graphite Gray, Octane Blue, or Red evo, I would have left them like this.
Second and final coat. There are a few images because I couldn't choose a favorite.
I washed her and installed the newly tinted side markers:
New Exterior Pictures
As alluded to in the previous post, I washed my Evo and took some pictures today. I spent almost an hour just cleaning the rims, as they were horrible from all the winter driving. The new pics show how nice she is looking with the black side mirrors and the tinted side markers.
Your car is beggin' for some Advans. So is mine, but I don't think I have the bankroll you have.
Advans? As in the Yokohama tires?
I have a full set in my basement. The stock ones only had a few miles on them when I took them off. I would have to pay to swap them over, or purchase some nice new rims. I like the second choice. I'm not sure if the woman will let me get new rims.
Looking good. I think he meant Advans as in the pricey ass wheels. And we could all use a nice set of those.
Ahh, yeah my rims could at least use a darker shade of gray. The actually look nicer as they fill with break dust. They almost look white after I cleaned them.
That is why I painted mine more of a brake dust color. Quick easy fix until I got the money together for some wheels (which happens to be now).
Advan wheels. The best looking wheels on EVOs IMO. There is a dedicated picture thread on EVOm. Check it out.
Those look good tinted.
Yeah I like the new lights man. I think all dark colored X owners should do that. I've used the VHT Nightshade before and it's really easy to use as long as you know not to try and get it blacked out in the first coat.
I had the day off today, so I was messing with the evo. I've been playing with the BOV to get it set right. I've also been getting some knock at weird times, like when I let off, and randomly during a pull. So I need to do some data logs right? Well ATR (AccessTuner Race) doesn't log my wideband, AEM UEGO. What does a Software Engineer do? How about right a program?
First, it logs my wideband via the serial port to a csv file with a time stamp similar to ATR.
Normal Serial Out:
Serial Data Logger's Out:Code:15.0 15.0 15.0 15.0 15.0 15.1 15.1 15.1 15.1 15.1
Then I take ATR's output:Code:15:21:07.438,15.0 15:21:07.458,15.0 15:21:07.458,15.0 15:21:07.478,15.0 15:21:07.488,15.0 15:21:07.508,15.1 15:21:07.528,15.1 15:21:07.549,15.1 15:21:07.569,15.1 15:21:07.589,15.1
And I merge it with the a/f file I outputed earlier. The merge is based off time stamps.Code:"Time Stamp","Boost Pressure","Exhaust Cam. Ret.","Ign. Advance","Intake Cam. Adv.","Knock Retard (CA)","Load Timing","MAF (g/s)","RPM","Throttle Position","WGDC Coarse (%)","Inj. Duty Cycle" 15:21:05.335,-8.05,-0.63,11.00,9.38,0.00,25,5,972,11,0.00,1.45 15:21:05.435,-8.05,-0.63,11.00,9.38,0.00,25,5,972,11,0.00,1.45 15:21:05.536,-8.27,-0.63,11.00,10.00,0.00,25,5,972,11,0.00,1.45 15:21:05.636,-8.27,-0.63,10.00,10.00,0.00,25,5,972,11,0.00,1.45 15:21:05.736,-8.27,-0.63,10.00,10.00,0.00,25,5,978,11,0.00,1.46
BAM! lolCode:"Time Stamp","Boost Pressure","Exhaust Cam. Ret.","Ign. Advance","Intake Cam. Adv.","Knock Retard (CA)","Load Timing","MAF (g/s)","RPM","Throttle Position","WGDC Coarse (%)","Inj. Duty Cycle","Air/Fuel" 15:21:05.335,-8.05,-0.63,11.00,9.38,0.00,25,5,972,11,0.00,1.45,15.0 15:21:05.435,-8.05,-0.63,11.00,9.38,0.00,25,5,972,11,0.00,1.45,15.0 15:21:05.536,-8.27,-0.63,11.00,10.00,0.00,25,5,972,11,0.00,1.45,15.0 15:21:05.636,-8.27,-0.63,10.00,10.00,0.00,25,5,972,11,0.00,1.45,15.0 15:21:05.736,-8.27,-0.63,10.00,10.00,0.00,25,5,978,11,0.00,1.46,15.0
Now I have Air/Fuel in my data logs.
Look what came in the mail today.
I got a whole case (12) of AMSOIL SSO, 3 quarts of MTG (for my tranny), 3 quarts of SVG (for my transfer case and diff), a filter for the Evo and a filter for our Scuby.
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