I have an LS turbo and iam using the MSD digital six ignition box with the 2 step rev limiter. When i hit the 2 step i dont build boost. How come everybody here is building boost at the line when they hit their 2 step? thanks

 

u shouldnt build boost because there is no load on the engine .... correct me if iam wrong... like when u push in the clutch and rev it up u dont hit boost....same thing

 

i though boost goes up when rpm goes high no matter what

 

no, theres not enough load on it in neutral...

ur all motor...

 

many members build boost at the line with a 2 step rev limiter...

 

i was under the impression that there needs to be some sort of load on the engine. for example when your car is just sitting at a stoplight and you rev it the BOV is very inaudiable, because there isnt much boost in the system. maybe i'm way off?

 

thats what i thougth too, but then i hear alot of people saying "im hittin my 2 step and building six psi at the line"

 

dumping fuel and retarding timing spools the turbo at the line. or at least thats what I hear

anyone?

 

........and shoots flames if you got a testpipe

 

i just wanna spool up the turbo and build some boost at the line for the launch

anyone?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DIRep &raquo;</TD></TR><TR><TD CLASS="quote">dumping fuel and retarding timing spools the turbo at the line. or at least thats what I hear

anyone?</TD></TR></TABLE>

Ahhh so that's why my normally quiet BOV was so loud when my car was in limp mode.

 

im always soo scared of using my 2 step rev limit due to the engine going soo lean when holding the throttle at full WOT at any RPM....my wide band always show us going as lean as hell... and if we richen up that area of lauchin that makes the rest of the fuel table rich... grrr
what do other ppl do in this case ??

Regards James

 

my car makes about 8psi on the two-step at 6000rpm.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BLKCRX &raquo;</TD></TR><TR><TD CLASS="quote">im always soo scared of using my 2 step rev limit due to the engine going soo lean when holding the throttle at full WOT at any RPM....my wide band always show us going as lean as hell... and if we richen up that area of lauchin that makes the rest of the fuel table rich... grrr
what do other ppl do in this case ??

Regards James</TD></TR></TABLE>
usually a air/fuel ratio is not going to read right on a two-step.i always go by egt.when i had a "helltech", the egts went off the scale and the pistons melted.with the stack ecu and the power fc they never go above 1350-1400.i assume the ecu may still be in closed loop when not moving.i am not really sure. on the "helltech" there was no map set for 6000 rpm at 8 psi.the only map set for 6000 rpm was about 20psi.

 

do it make any boost at lets say 4000rpms?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by turbotypeR &raquo;</TD></TR><TR><TD CLASS="quote">
usually a air/fuel ratio is not going to read right on a two-step.i always go by egt.when i had a "helltech", the egts went off the scale and the pistons melted.with the stack ecu and the power fc they never go above 1350-1400.i assume the ecu may still be in closed loop when not moving.i am not really sure. on the "helltech" there was no map set for 6000 rpm at 8 psi.the only map set for 6000 rpm was about 20psi.</TD></TR></TABLE>

doesnt really seem like a fault of the haltech, more like a fault of the tuner

 

two step is the bomb i build 8psi and launch at 6900 rpms it also helps your 60' time to i went from a 2.2 to a 1.73

 

i think there would also be a difference if you had a light flywheel vs. a heavy one
you would more likely produce some boost with the stock heavy (23lb) one, right?

 

If im not mistaken...You dont build boost with a 2 step..What it does is puts you in the rpm band were boost builds(4000-5800ish) so when you launch and you put load on the motor boost is already there...

 

You DO build boost on the two step if it's set high enough. It depends on your whole setup on how much boost you build. When the engine is on the two step it is seeing a load and will therefore spool the turbo. Chris is right about dumping fuel and retarding timing. That's something usually only done on race cars with big turbos though. Sometimes it's hard to get a big T series turbo to spool so you need to do this. By retarding the timing and dumping a bunch of fuel in, you delay the combustion in the cylinder and you don't get a complete burn because you dumped more fuel in. The raw fuel combusts in the exhaust manifold and creates energy to spool the turbo. You ever wonder what the large pop from some cars on the two step is? That's combustion happening outside the combustion chamber

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by VaporTrail &raquo;</TD></TR><TR><TD CLASS="quote">

doesnt really seem like a fault of the haltech, more like a fault of the tuner</TD></TR></TABLE>
that is correct.i was new to it and did not know any better.the thing is,with the power fc, that is one less variable you have to fool with.it is based on the honda ecu already so all of teh countless hours their engineers have spent goes to good use.

 

mines an LS with a REVHARD kit with the Precision SC34 turbo. I set my 2 step at 4000 so maybe thats why it isnt building boost at the line. I guess i'll try a higher rpm when i get some slicks. Im only boosting 5.5 right now.

 

So what is the correct way to tune a 2step so its efficient but not dangerous to the engine? Do you richer it up or lean it off ? when your on full throttle under load ? or do you just quickly hold the 2 step and launch hoping It doesn’t hurt the engine ? This has always puzzled me.

Regards James

 

my 2 step is at 3.5k and i'm boosting 11 at the moment and i know for sure i'm not suppose to make boost. although right off the line i get boost right away and it's sweet cause i get hardly any wheel spin...just a chirp and that's it.

 

at 3.5k when you hit your 2 step do you have anyboody just at a standstill witht he 2 step on?