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View Full Version : Build boost with Stationary Rev Limit?



oneillevo
07-14-2007, 01:20 PM
I was reading some EcuFlash threads over at EvolutionM and came across an interesting thread about the Stationary Rev Limit. I know this is probably an old topic now but I am so foreign to this stuff I hope someone can englighten me. This is the thread about the evo7base definiton: http://forums.evolutionm.net/showthread.php?t=200580&highlight=Stationary+rev+limit

Apparently, this old thread says that with the stationary rev limit you can build boost off the line. Has this been achieved? I am sure it has but Ive never payed attention. I was wondering if someone can teach me a little something today.

Limeyboy
07-14-2007, 01:33 PM
From what I recall it is possible with patching to the ECu firmware. Im sure someone will keep me straight. Personally, I think its a bit nuts to be building stationary boost on a street car. Track car, maybe, when you have the money for a new engine every now n then. Can just see it now, kids revving up at the lights for too long and .......

earlyapex aka jack ass
07-14-2007, 03:46 PM
Yes, depending on the level of mods on the evo you can build 10-12psi at the line. I can datalog my car to be totally accurate. Maybe I will go do that today. :)

lqdchkn
07-14-2007, 03:56 PM
Yes, depending on the level of mods on the evo you can build 10-12psi at the line. I can datalog my car to be totally accurate. Maybe I will go do that today. :)


Yup I was kinda busy at the christmas tree but I'm pretty sure I was making 7-10psi.Â* Launching with boost makes you faster. :D

Actually wait I did log a run with my Defi's let me go review it.Â* I'll tell you exactly how much I was making. :P


*Edit*
Ok I just reviewed my log and yes, 7-10psi (.5 to .7 bar to be exact). Varies as the revlimter "bounces". :thumbsup:

earlyapex aka jack ass
07-14-2007, 04:11 PM
Here we go. On my car, since it is using Ecu boost control is limited by whatever the WGDC setting is at the launch RPM, my limiter is set at 5500, so I am limited by 80% WGDC or so. I would imagine on a MBC car the launch limiter boost would be greater.

http://www.norcalmotorsports.org/users/bryan/mods/EVO/tech/launch_limiter_boost_EBCS.JPG

6-7 psi

oneillevo
07-14-2007, 04:45 PM
How is it done? Out of curiosity.

Bryan did you receive my email and pm?

earlyapex aka jack ass
07-14-2007, 05:32 PM
How is it done? Out of curiosity.

Bryan did you receive my email and pm?


How is the two step done? There is a setting in ecuflash you can set whatever limiter you want. The 03-04 evos have it set at it higher than the 7606 rev limiter so it is not engaged. They have the hardware however, so you can set your launch limiter where you want and walla! You now have a launch limiter. :)

I did get your email and pm, I have been on the dyno all day, just now getting to emails and such. :)

Limeyboy
07-14-2007, 07:54 PM
Im confused then. i thought the stationary rpm limit did not build boost on the line. i thought a patch was required to teh ECU? Maybe im missing something, but I know my gauge stops at 0 atmos while stationary, regardless of RPM. MY WGDC is 100 at 5500.

earlyapex aka jack ass
07-14-2007, 09:28 PM
You build no boost sitting bouncing off the rev limiter at 5500 Limeyboy?

Limeyboy
07-14-2007, 09:40 PM
nope. It will build boost with clutch in, but only when the car is rolling. When stationary, if i sit at 5500 and let it bounce a few times, the boost gauge never goes past zero. It swings up from vacuum all right, as the rpm climbs, just never past zero when stationary. Rolling with clutch in, it builds boost. Im going to double check all this tomorrow when im home to be sure, but thats what my memory is telling me now.

Should add this was the way it behaves, and always has, on a 2003 stock flash also.

steevo8
07-14-2007, 10:01 PM
^that sounds odd. What do you mean it will with it rolling? Do you mean with the clutch out and driving?

ST
07-14-2007, 10:50 PM
You build up a small amount of boost with the stock 2step. A couple of evom guys attempted to try to raise this boost threshold further by purposely retardinging timing at the lower load cells. However, they had mixed results and some driveabilty / part throttle issues.

oneillevo
07-14-2007, 10:57 PM
Im with Limeboy I build no boost just goes from vacuum to 0. Then again I am set at 5000rpms not 5.5k. Ill switch this and see what happens.

Positron
07-15-2007, 01:05 AM
i get like 3psi on mines

i set my forge mbc at 18psi peak.

Limeyboy
07-15-2007, 12:31 PM
Yep, stationary it will not build any boost. Clutch down, 1st gear (havent tried any others), rpm up at the 5500 limit, boost gauge never goes past zero. If I do the same thing (clutch in, in gear, rpms up to 5k or so) while rolling, it will build some boost (up to like 8 or 9 i think).

Perhaps its leaking through my throttle body seals, I will have to wait and see, but from memory, the car has always never built boost while stationary. It could be where the boost gauge is plubmed in, ill have to double check where they installed it.

earlyapex aka jack ass
07-15-2007, 04:57 PM
Do you guys have the pedal to the floor (100% TPS) or just giving it some gas on the 2 step?

oneillevo
07-15-2007, 05:04 PM
Giveing it some gas on the 2step, should it be 100 TPS?

Limeyboy
07-16-2007, 02:21 AM
I go WOt and let it bounce. Im going to double check on the way into the office later

Limeyboy
07-16-2007, 01:24 PM
OK, so I double checked , and it just goes to show that I dont launch the evo. It builds ~8Psi at the line, WOT in 1st clutch in with 5.5k limit. So ill shut the fook up now.

oneillevo
07-16-2007, 01:27 PM
I shall too! thanks for all the info on the matter.

Ben
07-16-2007, 02:55 PM
Isn't a two step a misfiring system which simulates load which in turn helps you build a good amount of psi? The when you press the clutch down to the floor and rev the engine it only lowers the rev limit. Someone correct me if I'm wrong.

oneillevo
07-20-2007, 01:12 AM
How is this possible?

http://mynesperformance.com/shop/images/media_gallery/videos/anti-lag.wmv

Was it me or did the gauge read 63psi? lol I could be way off. But hes only at about 3.5K and builds boost. Anyone car to inform a newb.

EVOVIII-WC
07-20-2007, 07:38 AM
How is this possible?

http://mynesperformance.com/shop/images/media_gallery/videos/anti-lag.wmv

Was it me or did the gauge read 63psi? lol I could be way off. But hes only at about 3.5K and builds boost. Anyone car to inform a newb.


I saw 63 PSI too on that electronic gauge on top of the steering wheel but that may not be boost. Could it be oil pressure? Here is the link to the specs on that car:

http://www.mynesperformance.com/shop/shop_cars.htm

It's using a Motec M800 not ECUflash. In this link in EvoM, they said that their boost is at 26PSI pushing 520whp.

http://forums.evolutionm.net/showthread.php?t=274829&page=2

oneillevo
07-20-2007, 09:49 AM
Ahh. So its was another ECU. Is it possible to build boost at 3.5k rpms with our stationary rev limiter? or pretty much only at higher rpms will we see boost begin to build?

EVOVIII-WC
07-20-2007, 01:00 PM
Ahh. So its was another ECU. Is it possible to build boost at 3.5k rpms with our stationary rev limiter? or pretty much only at higher rpms will we see boost begin to build?


I think you can build boost at 3.5k rpms with a combination of a non-stock turbo(like the TME, etc.) and some engine upgrade/tuning like cams, etc. Remember, this evo is heavily-modified.

The 05 and above models have that limiter set at 5k(I think) from the factory maybe because that is where the boost begin to build on the stock turbo. The experts can clarify that.

oneillevo
07-20-2007, 01:08 PM
The 05 and above models have that limiter set at 5k(I think) from the factory maybe because that is where the boost begin to build on the stock turbo. The experts can clarify that.


I know the 05+ stock rev limiter is set to 5K but I was wondering if we set it to 3.5K would it be possible to build boost?

MarkSAE
07-20-2007, 01:11 PM
You'd never be able to launch properly w/ the stationary rev limit set to 3.5k. It's just not enough RPM to spin the wheels.. you'd bog for sure.

oneillevo
07-20-2007, 04:10 PM
You'd never be able to launch properly w/ the stationary rev limit set to 3.5k. It's just not enough RPM to spin the wheels.. you'd bog for sure.


Totally forgot about bogging, lol REALITY CHECK PLEASE! lol

lncrevoviii
07-31-2007, 09:14 PM
well, I have noticed two things.

While doing two step, my car builds boost to about 10-12psi.Â* It gives the normal BRAP BRAP BRAP, with about less than a 1/2sec pause.

After, installing the Greddy RS Bov, I put the car in neutral and went WOT. The boost spiked 22psi, the fart sound was like a mack 10 BRRRRRRAP BRRRRRRAP BRRRRRRRAP rapidly, when I let off, the VTA gave a nice loud WHOOOOOOOOOOSH. Some car alarms were set off, friends noticed fireballs popping out of the exhaust and into the cloud of black smoke which was mezmerizing. The thing is I have never done that before going VTA. I just wanted to see if the car can build boost in neutral. Well, it does and does it very well. I am pretty sure I won't try that again. :p

Limeyboy
07-31-2007, 09:33 PM
22 PSI with no actual load :shock:

Matz
08-31-2007, 11:31 PM
chrisw was asking me at the last autox if I had this feature enabled -- I don't. However, it would be interesting to try it just to see what happens. I'm really, really, REALLY slow off of the line because I don't have refined clutch technique (the Evo is my first manual and I still suck at it). But if I do this, I guess I risk killing my clutch / drivetrain?

Evo9R
08-31-2007, 11:57 PM
you still have the stock Clutch

Matz
08-31-2007, 11:58 PM
you still have the stock Clutch


No, I have an ACT 2900

Evo9R
09-01-2007, 12:01 AM
just use the two step and let it rip :D

ReSin
09-01-2007, 12:28 AM
chrisw was asking me at the last autox if I had this feature enabled -- I don't. However, it would be interesting to try it just to see what happens. I'm really, really, REALLY slow off of the line because I don't have refined clutch technique (the Evo is my first manual and I still suck at it). But if I do this, I guess I risk killing my clutch / drivetrain?


The beauty about most SCCA events, is that by the rules, there has to be at a minimum 45 degree corner within 75 feet of the start line (or something to that affect)...so you can't really 2-step it off the starting line.Â* I'll give you some pointers if you'd like at the GGLC...free of charge...

Â* Â*Dennis

kinetics
09-01-2007, 12:50 AM
ok a newbie question guys..coz i don't really drag my evo
what is the "two step"? how is it done?

TIA

Matz
09-01-2007, 07:08 AM
ok a newbie question guys..coz i don't really drag my evo
what is the "two step"? how is it done?


My understanding is that the ECU is capable of using a different rev limiter when the clutch pedal is pressed. So if you're at a light, you can keep the clutch in and press the accelerator so you're WOT, and it will limit you to XXXX revs. Then drop the clutch and you're off. :)

joshesh
09-01-2007, 08:20 AM
launching at most autox courses will not do you much good. But your stock rev limiter at 5500 gets around 10 psi boost from launch, I think.

Matz
09-01-2007, 12:00 PM
launching at most autox courses will not do you much good. But your stock rev limiter at 5500 gets around 10 psi boost from launch, I think.


Very true, that's something I like given that I don't know how to launch. However, I feel that I'm a bit more sluggish that most drivers from the get-go, so I was thinking that every little bit would help me. :)