ohsnapzafingcu

iTrader: (2)

stock k20a2
-sidewinder, tial 44wg
-garrett t3/t67 journal bearing turbo
-MAC boost controller for bbg, boost controlled by kpro
-no noticeable boost leaks

no matter what my target PSI is, 4th and 5th gear make 18-20 at the revlimiter...and that's PLENTY of load to make my desired PSI at 6000-7000 rpm.










No matter what I set my boost tables too on kpro, it doesn't make my desired boost PSI until right at rev limiter. Is something wrong with my MAC solenoid?

ohsnapzafingcu

iTrader: (2)

don't mind the TPS, connection was bad. got it fixed.

CO_RaceFab

how is your solenoid setup?

Spawne32

iTrader: (3)

you have a stock k20a running a 75lb/min turbo

CO_RaceFab

Dude are you serious? We use a 95lb/min turbo on a stock bore stock compression b series it has a 4000rpm power band. This guy is racing this car not having a 400hp pissing match like you fi section guys.

D-Rob

What does the boost curve look like with the solenoid disabled?

I'm going to assume it creeps, since it's a 67mm with a single 44mm gate on a sidewinder manifold K-Series.

Using fixed duty on BBG settings on a boost curve that has creep will just continue on the same shape until you really start getting the boost up there.

Spawne32

iTrader: (3)

on a stock k20a?

ohsnapzafingcu

iTrader: (2)

https://www.google.com/search?q=kpro...tm%3B696%3B376
Per instructions and diagrams on k20a. Would it be better if i took a pic?

I haven't ran the solenoid with it disabled, but it's a 4 psi spring (iirc, or maybe a 3.5?) and the least i can get out of it is 7-9 psi because of creep.

D-rob, do you have a dyno chart of your car making power in the 400-500 range? Checkout my dyno graph, looks like i have a supercharger!

ohsnapzafingcu

iTrader: (2)

the dyno was at 19psi right at the rev limiter

D-Rob

It looks like the boost plot would have the same "creep" curve to it on that sheet.

Try more duty in the middle, tapering off at higher RPM.

Email me a datalog and your current calibration, and I can show you what I mean.

CO_RaceFab

Yea a smaller engine and yea why not I have seen lots of fast times out of stock k series motors. Op how is your plumbing in and out of the solenoid hooked up I have seen the a few times, also who is tuning the car?

ohsnapzafingcu

iTrader: (2)

Boost solenoid

And more of the upside.


Here's a screen shot of my boost control parameters.


I won't be able to provide another datalog on higher boost (16-20 psi) until tomorrow. it's been raining all day :/

ohsnapzafingcu

iTrader: (2)

Tuned by me

D-rob. Sending email of my tune to you, now

Turbo-LS

iTrader: (4)

Whats the frequency set on the solenoid controls ? You will have lazy boost with a 4 psi spring and a single 3 port solednoid either way but you shoudl correct the creep issue first. The add a second 3 port solenoid or switch to a 4 port and boost will come on quicker with such a small WG spring.

mar778c

iTrader: (1)

Best reply I've seen in a long time. :props:

ohsnapzafingcu

iTrader: (2)

How do i check the frequency of the solenoid controls? sorry for the ignorance.

I don't have a creep issue, the only issue i have is when i'm trying to make spring pressure and it rises to about 7-9 psi. My dyno graph I showed is what i'm making daily, and my daily target PSI is between 18-20 psi.. Right at 560 WHP. The datalog i posted in earlier post was for reference of what my boost was doing.

What the heck does a 4 port solenoid look like? Sorry i'm still learning alot about turbo components, all i know how do to is TUNE!

Turbo-LS

iTrader: (4)

If you are running a 4 psi waste gate spring and your getting 7-9 pounds of boost then you have boost creep. It doesn't have to continuously go up to be considered creep. Anything over target pressure is creep. Of you switched to a higher spring pressure in the gate it would build post much quicker in the rpm
Range. The 4 port connects to both the top and bottom of the waste gate and controls boost more efficiently that way allowing the gate to stay closed longer and build boost quicker

ohsnapzafingcu

iTrader: (2)

The next set of springs i have are the large red (10.1psi) and large green (11.6psi) I'm going to go back to the large red spring and re do my boost control tables. This is originally what i ran and man i popped flames out of my dumptube for DAYS. i switched to the smaller spring and it stopped doing it :/. My guess is because it built the boost so quickly?

I'm going to install the red spring tomorrow and throw some fresh plugs into the motor and see what it does. I'm not looking forward to redoing the boost tables for the new spring :/

crvtectim

You should also give the mac valve a dedicated boost ref. source only. You have it plumbed to your vac block, which of course sees vacuum as well as boost and the mac valve should only see boost ref.

ohsnapzafingcu

iTrader: (2)

How do I do that? Tee off the line from the compressor housing to the bottom of the wg? Theoretically it'll still see vacuum

CO_RaceFab

this is golden advice number 1 should be to split to the intake manifold or compressor housing and bottom of gate and 2 should be plumbed to the top of gate. those solenoids don't wake up for me at those dc percentages but that's just food for thought I don't know what your percentages yield as every car is different. I would try lowering your activation pressure also because with a 4 psi spring you pretty much have to max the spring out to get the solenoid to even fire.

ohsnapzafingcu

iTrader: (2)

I don't get what you tried explaining as far as the vacuum lines go?

If i change the solenoid activation to 1psi will it change my tables for pressure vs duty cycle? Should I set it even lower? Like .25 psi or something?


My new plugs will be in after work, gonna re gap them and play with the boost tables a bit. if it doesn't bring on full boost like i want it, i'm going to switch out the WG spring to the 10 pounder. Sucks, because now how I have it setup i hookup in every gear :/

CO_RaceFab

as far as changing the duty vs % no changing the activation pressure wont change those and yes you can set it at .25 which in theory would make it come on even faster. but you need to have a solid pressure source as this is where the pressure that is being applied to the top of the gate actually comes from.

cruizinmax

iTrader: (2)

I can't say for certain but I would think having the boost control solenoid coming from a different boost/vacuum source than the bottom of the gate would cause a problem. The bottom of the wastegate is coming off the compressor housing and the solenoid is going through several hoses/vacuum block on the other side of the intercooler, ect. The bottom of the gate is seeing pressure before the top and it has less psi. I bet it is causing the gate to crack open well before your target boost.

I would try running a tee from the hose on the compressor housing and attaching one end to the boost solenoid and the other to the bottom of the gate. See if that has an effect.

ohsnapzafingcu

iTrader: (2)

D-rob is going to redo my tune and have more duty cycle from the solenoid so I receive full boost earlier. I'll load it and see how it goes, if it still doesn't work i'll go ahead and re-route my vacuum lines