Why does your vehicle weight change in almost every one of your VD plots?

 

Because deleting 200lbs makes it more accurate. At least as accurate as a dyno. Not a dynojet though, those suck.

 

I've never used the program. I was just curious. It seems to me that something like weight would be critical to the accuracy. Another variable you wouldn't need to worry about on a dyno. Right?

In line with things like road surface, wind speed, wind direction. I think the most important part of using something like that program as a tuning aid is to do the test the same way, in the same gear, on the same road and do it in both directions and somehow take an average.

I can see the merit for the software....just trying to get my head around it.

 

Your fabrication skills! Thanks for this build and write up!

 

Yes you enter gear ratio, tire circumference, and weight. Then you data log a pull, tell it what gear you were in, and it finds it in the log to create the dyno plot. Obviously if you can accelerate an object weighing X from 0-60 in Y seconds you can calculate hp. But that weight needs to be spot on, and yes road conditions matter.

 

You are exactly on point , The software is only as accurate as the end user makes it . When done correctly it's actually extremely close to a real Dynojet . That's why I do all my runs on the exact same road using a marker to start the pulls, same weight, same everything, so they are as identical as physically possible. as soon as you deviate from that you get sporadic results which we've all seen done. Even if his weight is off by 200 pounds though he still well over 350 wheel

As soon as this set up is figured out and he says it's done we will all demand Proper plots and 1/4 mile slips. That should settle things once and for all

 

No question it's got to be making power. 30 some odd psi and 17 degrees timing...It doesn't have a choice but to make power. That's not what I was saying or infering. I was just wondering if there was a reason to change the weight around that I was somehow missing.

 

I want a ride in this car.

 

A miracle.

 

It has two sources as I'm using external wastegates for each turbo. For the front turbo, bottom port goes to the intercooler pipe post-intercooler and has a MBC hooked to it now. The top port goes to the compressor inlet.


Some pulls were with a passenger, some are not. I updated the weight (and outside temp) to keep it as accurate as possible.

Thanks man! It's got over 250 miles on it so far and it's working great!

This.

Well over indeed. I should make a new video, I will once the muffler gets installed for sure, maybe before. It's nuts at this power level.


I'm in Houston, TX. I'll be racing at HMP every Friday night that this runs (will be racing other car there if this one does not run). You're welcome to ride along if you like, or if you are just in the area one day I'll take you for a spin through the gears.

 

A start is deleting this avatar I was given.

 

It's a very handy tool to use when tuning. You will note on some of the plots I posted, I ploted two pulls and they were overlapping each other fairly close. I used to to play with AFRs to see what it likes, and see the power change as the boost changed. I can adjust which turbo makes how much boost, and see power change at the same total boost by shifting which turbo does how much work. Big turbo winning in the power department, little turbo winning in spool.

 

When you were first talking about this I wondered about there being enough energy left in the exhaust to spool the rear turbo. (I'm a layman) But I see. I see More air, more fuel=more energy. More air, more fuel=more energy. Serious horse power you've got.

 

You know, if you were a subscriber, you'd be able to change it yourself.






949 Racing

 

Yeap. The big turbo probably wouldn't spool on its own until 8,000 or so. The little turbo gets enough air/fuel/energy going to light it off a lot sooner. This is the part that I was unsure about going into this. In theory it would work, but I'd never done it so wasn't 100% sure. But it does work like that.

 

I have a question for you guys.

I would like to setup the boost control to do the following:

Small turbo wastegate stays pinned shut until I hit 30 PSI, then it opens and regulates the small turbo to 30 PSI.

As the big turbo spools, I want boost to climb to target, which is 38 PSI.

Once I hit 38, I want the small turbo so seamlessly reduce it's boost level from 30 PSI, to 19 PSI, while the big turbo climbs up from 8 PSI to 19 PSI.

This would result in the boost going from 0 to 30, then 30 to 38 and holding 38 to redline, while maximizing torque to the wheels, spool, and top end power. The little turbo spooling high and hard gets the torque up fast, and helps spool the big turbo fast.

How could I actually set this up? Simpler the better of course. Would love for this to be mechanical if possible.

 

I think you need dual ebc's for that. And it's a good idea because that 2871 will not last at 30psi. When my buddy used an ebay gt35 it would always fail in a few months past 25psi

 

Oh yeah no doubt this small turbo can't hold high boost at revs. My garrett died the same way, pushing it too high up top and it failed (killed a steel 270* thrust bearing)

Could you elaborate on EXACTLY how you'd hook it up, and control it with dual ebc's? I'm trying to figure out any way to actually make it work the way I want, and if it's electronic, limiting the little turbo's max boost to say, less than 5,500 would probably be a fantastic idea for reliability.

 

something like dis?


949 Racing Emilio TSE Trackspeed Andrew

 

So those pics show duty % and targets. Do you have to have both for closed loop? Also does MS's closed loop actually work correctly/not overshoot/undershoot a lot? Would be awesome to have MS do this if possible.