TTZ06VETTE

For those of you set up with Boost by Speed I could use your insights as I attempt to change my Eboost2 configuration from RPM based boost to Boost by Speed.

Current Setup:
Twin turbo GT30 LPE build with max boost at about 18-20PSI (limited by intake design)
I use an Eboost2 controller with RPM based boost curve setup and max duty cycle at 80% or about 16lbs.
Engine is LS7 block with forged internals, low compression @9:0:1 and meth injection and MAF tune. Dyno'd on Mustang at roughly 850/850 WHP/WTQ. Not trying to change anything here.

Car runs great but 1'st/2'nd gear are useless from a traction standpoint. Would like to try going with Boost by Speed and keep my current max RPM based boost/duty cycles to avoid a complete retune (I do have HP Tuners however).
I received the new LPE STOV-004 Boost by Speed controller to accomplish this. The controller picks up the VSS signal(I understand the limitations from rear wheel spin), and uses the pulse to define speed threshholds for increment and decrement boost settings in the Eboost using the Sequential Swithching Function B option.
I have all the wiring figured out, I just need some feedback on the "speed brackets" I should use and the boost duty cycles associated with them.
I took a stab at a baseline that allows 1's and 2'nd to basically use the wastegate spring then gradually increasing duty cycle in taller gears as traction becomes available. The table attached is roughly the speeds attainable in each gear at RPM.
This obviously would differ by gearing, wheels, and tire sizes but should be ballpark.
My current RPM boost duty cycle settings are in the bottom row of the table and my new Boost by Speed duty cycle setting based on speed groups are on the right.
It would be great to get some feedback from the forum on this to see if I am thinking about things the right way and if someone can share their experience in setting up their Boost by Speed.
Thanks in advance!

5 Liter Eater

This is a neat chart. I definitely think you're setting it up correctly. You'll just need to play with the duty cycles in each gear to get it to where you're not leaving power on the table or spinning at WOT. Also it will depend on road conditions. So if you set it up to the max on warm concrete it'll most likely still spin on cold asphalt.


I received my LPE box too.



Unfortunately my car is down to refresh the motor so it'll be a few weeks or more til I get to test it out but I will have it all wired up prior to fire up.


I have something similar in mind as you do.
1st - 15# (gates)
2nd - 17# (??%)
3rd - 20# (50%)
4-6 - 25# (70%)

I may also lower my gates back down to 10# and run 10/15/20/25.

TTZ06VETTE

Thanks for the feedback 5 Liter!

5 Liter Eater

My pleasure. Let us know about the EBII beeping! Not sure it beeps when it goes up and down in SSB mode.

TTZ06VETTE

If anyone else has Boost by Speed setup, still interested real world feedback.

Unreal

Friend just finished a GM speed switch. Can set it to whatever speed you want and it switches. He uses this with boost controllers that have a single input so that at whatever set speed it goes from low to high boost. Super easy to adjust, works perfect. Isn't as fancy as what you guys are doing, but it is cheap, simple, and works.

TTZ06VETTE

You could also set this unit up the same way to basically turn on and off from no boost to full boost at a set speed but it also gives you the resolution to bring boost in gradually at different speeds. I know there are a few folks here that have used boost by gear or are using aftermarket ECU's that allow this (I.e. ProEFI). Wondered how they brought boost in based on speed to make best use of traction and gears.

Ls240sx

Thats a neat little box! I had no idea that existed.

5 Liter Eater

It's brand new. We're beta testing it.

5 Liter Eater

You get this wired up yet?

TTZ06VETTE

Been on the road for work. Got the wiring from Eboost and VSS stripped and ready to solder to the STOV. Also configured a new tune file reducing timing in the low RPM area where the car will see boost in 5th and 6th now vs. higher RPM. May leave fueling alone in this area until I check out AFR's.

TTZ06VETTE

Guys...finally got my STOV-004 LPE Boost by Speed wired up and working.
Although the module performs as advertised, if you do use this device or are going from a Boost by RPM to Boost by Speed setup like me, there are couple of things you need to be concerned about. First, as others have said, the tune does have to be tweaked. I had significant Kr in the low RPM ranges of 4th-6th gear that required me to pull some timing in those ranges and accelerate my meth curve delivery. Nothing drastic but something to be aware of. My boost now ramps up prior to peak torque, so I needed to be sure I had adequate fueling and less aggressive timing in these ranges.
The real show stopper for me was my clutch. Unfortunately when LPE designed my drivetrain they installed an Exedy GTO4SD twin which was fine when the majority of boost was delivered at or after peak torque (approx 4500RPM). Now with boost by speed I have 75% boost coming on earlier in the higher gears(especially 5th@ about 85MPH)
I now have MAJOR clutch slippage with this clutch. I keep lowering boost and Wastegate pressure but it is not working. When I get into boost at 3-3.5k in 5th, I go from 3k - 6.5k RPM and MPH only increase incrementally <10MPH. CLutch is slipping BAD.
So that leaves me in a situation of installing a new clutch or going back to Boost by RPM. Think at this point until I need a new clutch I will go back to Boost by RPM. Those with capable clutch should be O.K.
Hope this helps.

wesam

Please i need more information about this setup
i have a single input boost controller that i'm willing to use this technique with
any help will be appreciated

Unreal

http://www.agpturbo.com/mph-switch/

BIG GUN

You need to also consider just how low you can target boost and how hard your turbos hit.
If you cannot make less than say 9-10psi on springs, then the car will still spin like crazy in 1st-2nd and then ramp up.

I run a similar setup with an LPE 427 but I'm running GT28rs.

I can do RPM ramp -OR- speed ramp via an HKS EVC boost control. When I set the speed ramp, the torque spike in 1st and 2nd still spins like crazy (345 NT05rs). When using the speed ramp, I lose the RPM correction. At least with the efficiency of my little turbos, the boost drop over the rev range is significant. So when corrected on speed, after it hooks in 3rd, the boost drop up top slows the car down. I've run it at the track like this and it costs me MPH. I've opted to keep the RPM correction to keep the curve flat and while it still spins in 1st/2nd/3rd-ish, once it hooks it pulls harder to 6500rpm.

So basically, in my case, the speed ramp made 2nd gear faster and slowed down 3rd/4th/5th.

Also, I smoked my excedy clutch. Tried an RXT and it slipped / had crap manners. Settled on a ZR1 clutch and it's awesome (approx 900rwtq).

Hope this helps,
Scott

TTZ06VETTE

Thanks for the info Scott. This makes sense. My turbos are a little bigger than yours with the 1000HP upgrade but they exhibit the same type of behavior as the 28's
With he Boost by Speed setting 1st through 3rd was actually quite linear. I reduced Gate Pressure as well which seemed to slow down the torque spike. But now I have the clutch slip in 4th-6th. I think if the clutch held it would have worked.Wish they would have installed the HD Exedy vs. the SD at least. Not ready to tear into the drivetrain at the moment. Another failed experiment and waste of $$.

Here were my boost/speed settings. As you can see I wasn't even at maximum duty cycle.

TTBlueZ06

I really like this setup.. I think I am going to do the same thing, likely gonna have to pick your brain in the near future.

5 Liter Eater

The LPE box is a lot more extensible

TTBlueZ06

For the money and lack of messing around.. I think this controller may be more worthwhile.. Can read speed and RPM via OBD port..


https://www.amsperformance.com/cart/...ontroller.html


Anyone ever use one of these?

Unreal

Yes it is, but for cost/ease of use for a lot of people, the AGP switch works great. Setup 3 of them and they all work perfectly and install quickly.