ericwarren

hello all.
i have a stock 94fd with hks dp and rb dual tip catback.
i was seeking boost in the 11-12 rage (11-9-10) with just those 2 mods so i installed a profec type-s.
Installed by replacing the small hose (with pill) and then capping the wastegate nipple and the hose that was connected to that nipple.

now boost is at 10, but the transition is a bit low...10-6-10 in 3rd gear.

Any turbo/boost controller experts have any ideas. I've searched and see others have had this but not sure of the solve, or if it is even necessary.

thanks!

tom94RX-7

iTrader: (5)

I think you could put a valve into the turbo precontrol line and adjust the transition then, open the valve more to decrease the boost dip during transition. I have a Home depot valve in the precontrol line, although after many tries I can't seem to get a transistion high enough like it should be, mine is always a little larger dip than I would like. I have a ball and spring mbc in the wastegate line.

rynberg

Eric, I would try playing with the balance **** a bit more to see if you can reduce the dip -- I would try going more "sharp" with it first. Just remember that turning the balance **** to "mild" will raise boost levels, so be careful.

If that doesn't work, you can do a little bit of low transition troubleshooting. I would view installing a valve/different pill in the pre-control as a last resort as it is very difficult to get fine-tuned.

ericwarren

thanks guys!
tyler, just to clarify, turning the gain (balance ****?) to the right (or increasing the gain) should be tried to lessen then transition, but that can also result in an increased level of boost, is that true?

rynberg

If Greddy changed the name of the **** to "gain", then it should still work the same -- turning the **** to the right should result in "faster" wastegate response and slightly lowered overall boost levels. If you go too far, you will get unstable wavering boost up top. I would try to experiment -- full left and full right, to see how the gain **** effects your transition. Just be careful when turning it full left as your boost levels will increase.

I went through a low transition problem and it turned out to be the check valve between the y-pipe and pressure chamber was hinky -- and eventually broke in half!

adam c

iTrader: (2)

If you don't mind swapping a pill in the precontrol line, you may have the parts already. I was having a low dip at transition 13/7.5/13. I have a needle valve in the wastegate line. I took my old wastegate pill (slightly larger opening), and put in place of the pill in the prespool line. This increased my transition to 9, and really smoothed things out. I wouldn't mind if it were slightly higher, but it is a good improvement.

ericwarren

i'll give it a try....
i have the manual in front of me, however, it says something somewhat opposite...i believe the functionality of this know has slightly changed with the type-s.

1) it says to start with about 30% gain
2) if spikes occur: lower gain
3) if boost is inconsistent: increase gain
4) to improve boost response: increase gain

*** turning the gain toward min will decrease the boost, and turning the gain toward max will increase the boost.


i tried it at 20-40% and still the dip, i'll raise it a bit more (and lower the boost to compensate).

ericwarren

hi adam...
i should have been more precise in my 1st post, as i removed the shorter hose that should have the pill in it (but my 94 seems to have the pill built in to the nipple) so i'm actually pill-less.

I just re-checked all my fittings, my cappings, etc and all is perfect.
i'll tinker with the gain in a few min.

anyone else have the type-s care to post their settings?

rynberg

Eh, it looks like Greddy had to go and muck up the simplicity of the balance ****.....

The old balance **** increased the sharpness of the wastegate response profile as you turned it to "sharp" -- this should allow quicker boost response but too sharp a profile will give you wavering boost up top (and lower boost levels overall). Lowering it to a mild setting slowed the response, increasing lag, increasing the chance of spiking at transition, but kept boost more stable up top. It's a balancing act.

I can't imagine the new gain **** works much differently, despite the name change it's still controlling the wastegate response profile.

ericwarren

i'm back from my test run....
the increasing the gain definitely has an impact on the boost, higher the gain the higher the boost....so to compensate I did the following:
-raised the gain to 50% and lowered the boost to 25%: result similar
-raised the gain to 100% and lowered the boost to 20%: result similar
-lowered the gain to 0% and raised the boost to 40%: you guessed it, similar....

of course there were lower boost #s along the way, and there was lower transition as well (as low as 5).

for the heck of it, i turned it off, 7-5-7 or so.

have you ever tried this set up, but with not capping the other nipple/hose from the wastgate? what is the result or expectd result?

and just to double confirm i have used the right ports on the solenoid....

I followed the directions for the actuator type installation : so i used the COM port and the Never Open (NO) port.

I did not use the external wastegate setting, which asked for the COm port and the Never Closed (NC) port.


Is it possible that the lower airbox hose may make a difference in transition if not perfectly on? it look slike it is on perfect, but that is the only one that gave me fuss.

thanks
e

rynberg

This is the problem with these cars -- everyone is different. You do not want to uncap any nipples/lines! Your installation sounds correct to me.

It's possible that something in your control system is not 100% up to snuff -- I mentioned that check valve earlier -- or it's just that the pre-control needs to be adjusted on your car. The fun of the sequential system.

BTW, it sounds like the gain **** is NOT exactly the same thing as the Balance **** on the old Profec B -- bummer. The adjustment procedure should be the same in any case.

ericwarren

these cars sure can be fun

the kicker is that the transition was fine prior to the controller and i'm fairly certain i didnt muck anything up when i installed the solenoid...oh well, I guess all the little quirks are worth it to have such a cool car. BTW, is there any "risk" associated with a 10-6-10 pattern, besides the minor delay associated with the dip?

and it feels darn quick to me....i felt quilty doing the test in 4th gear, as I was going 90 or so at time of transition.

adam c

iTrader: (2)

Having a transition at 6 psi will not hurt anything ..... but it will bug you

ericwarren

ok, time to order random new parts and hope i solve the problem i guess..

i'll start with the tubing and check valve from the y pipe to the pressure chamber.

any other thoughts/ideas while i'm at it?

ericwarren

I did some more searching and uncovered this post.
it seems to make sense.....can someone confirm this actually happens, as it would explain my issue!
thanks
eric

-----------
Ibumar
Registered User
*
Ibumar is Offline:
Join Date: May 2003
Location: Illinois
Posts: 75



I just noticed you say you have a profec installed. I had the same problem after installing my profecB. Here's what I figured out....
Because the boostconstroller controls the wastegate independently of the ECU, it opens the wastegate more below 4500 than the ECU would. This ECU primarily uses the Precontrol to manage boost between 3000-4500rpm, and the wastegate stays mostly closed.

The boostcontroller doesn't know anything of the sequential setup, it simply opens the wastegate to maintain certain level of boost pressure. The result is that more of the exhaust is bypassing the turbos completely below 4500, effectivly reducing the amount of exhaust pressure available to spool the secondary turbo prior to transition. Basically the opening of the wastegate by the controller is robbing energy from the prespool of the secondary. To counter that the prespool door needs to be opened further. This can be accomplished by switching to a larger pill in the line from the compressor housing to the prespool actuator, or installing a needle valve, or a number of other ways....

I installed a needle valve in the line to the prespool actuator and used that to adjust the transition... My transition has gone from 10-6-10 to more of a 10-9.5-10.5-10. It is very quick now. The very noticable drop in accelleration is replaced by accelleration followed by even more accelleration

I would try this first before tearing even more apart only to come back to this.
Hope this helps.

<edit>
Just thought about this.... Do you have the restrictors in the nipples like some of the 94-95s do? If that's the case, I think you could install another restrictor on the side of the actuator that goes to the solenoid to achive the same result (more pressure on the prespool actuator).

potatochobit

iTrader: (1)

hmmm. i slightly have this issue also.

looks like someone needs to do a writeup and get part numbers of this needle valve.

tom94RX-7

iTrader: (5)

I have a low transition and low primary boost problem (maybe its a problem), my boost pattern is usually something like 11-8-14 in 3rd and 4th gear. I have the Home depot needle valve in the precontrol hose, I kept opening it and it never really did bring my transistion high enough, and the more you open it the more you lose primary boost. So since I usually just boost on the primary turbo, I closed the precontrol valve more so I could get a little more boost on the primary turbo, the more you open the precontrol valve the more the primary boost goes down when you have another mbc in the wastegate line. And it's not boost creep getting me to 14 psi because it gets there quickly when the 2nd turbo kicks in, and it doesn't get any higher depending on the mbc, and I keep keep it lower by opening the wastegate valve more.

There is tons of info on the needle valves, do some searching, I followed this site - http://www.robrobinette.com/boost_controller.htm

ericwarren

anyone think that the length of hose to and from the controller's solenoid have any impact here?

i replaced a 4" hose with 3-5 feet oh bypass hose.

thanks

adam c

iTrader: (2)

I absolutely believe that the long hose in the prespool valve causes a problem. Adjusting a needle valve in that location is nearly impossible to get right. Just because Robinette did it, doesn't mean that it works. The long hose for the wastegate line doesn't seem to create any problems.

I believe a larger pill, or another type of controller is required for the prespool line.

ericwarren

i spoke with greddy today...
they suggested i turn the boost and the gain up...
does anyone know how big an impact gain has on boost, from 0% to 100%, and the reverse.
are we talking <1psi, 1-2 psi or >2 psi?


thanks