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Will work for Supra parts
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Discussion Starter #1
My Supra had a Blitz DSBC installed by the previous and I didn't get a manual with the car, but I did however find a really helpful site linked from MKIV.com.

When I got the car the limiter was set at 1.10 km/cm2 and I saw the peak recorded value was 1.30 km/cm2, or about 18.4 psi. That's a bit a over boost, so I went through and reduced some of the settings due to me not being able to monitor the a/f ratio (no a/f or boost gauge installed by the previous owner). Under Modes 1 - 4, I saw different settings for the Ratio, in increasing increments of about 25, up to a max of 75. The Gain setting was at 0.

I reduced the limiter to 1.00 km/cm2 to be safe, set the Gain for 7, and set the Ratio for 30. I haven't hit the overboost warning and the car runs pretty good at the above settings, but the boost seems a little slow to come on. If I'm looking to increase the response of the turbo's spool up (make them spool faster) it seems there are two ways to do so. Turn up the Gain, turn up the Ratio, or do a combination of both.

The question is, which would be better to adjust in order to get faster spool up with the stock turbos, in sequential mode? Gain or Ratio? Which would have a greater effect? Obviously I don't want to overboost as much as the car had been, so what numbers should I start playing with 1st and how high should I go with them?

I'm sure every car is different, but in general how close or far off are your Gain and Ratio settings compared to one another, and how does the car boost?
 

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its a slow auto...
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you have to play with the gain and moniter it as you make changes..make small changes and make sure your not over boosting... right now with my single turbo i have my gain set to 19... with weather changes i change the gain too, when its cold out the car will tend to ramp up the boost to fast if i have the gain set higher then 19 and it will hit my boost limiter..
if you want to be sure on how much boost your making at different ratios, then you would turn the gain down like you had it and only move the ration and watch the boost level under high load(ie, do a little run on the highway and watch your boost gauge) once you figure out where you want that, then start turning the gain up slowly.. its trial and error....

jay
 

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To make it simple, ratio is how much boost, gain is how fast it comes on. Like jaynite said, experiment. If you are hitting 1.3 with the limiter at 1.1 it should be limiting boost. My older DSBC turns red when the limiter activates. I think I've got the gain at 100 with my T78 to reduce lag as much as possible. Then I've got the modes set like you, something like 25, 50, 75, 90 so I can just turn the knob when I need more boost. Just play around with it until it does what you want.
 

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Discussion Starter #4
Well this helps a bit. So if I understand this correctly, ratio is a percentage of your max set value for the limit? Kind of like a high and low boost setting, but with 4 levels - one for each mode? If that's the case, with my limiter set at 1.00 and a ratio of 30, I am most likely not making the full 1.00 of boost? I really couldn't pay attention to the digital gauge on the boost controller to see while driving. I really need an analog boost gauge, bad!
 

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its a slow auto...
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supra400hptt said:
To make it simple, ratio is how much boost, gain is how fast it comes on. Like jaynite said, experiment. If you are hitting 1.3 with the limiter at 1.1 it should be limiting boost. My older DSBC turns red when the limiter activates. I think I've got the gain at 100 with my T78 to reduce lag as much as possible. Then I've got the modes set like you, something like 25, 50, 75, 90 so I can just turn the knob when I need more boost. Just play around with it until it does what you want.

holy crap... your gain is set at 100 and you dont have spikes?

jay :dunno:
 

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Supra Owner Since 1996
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Recommended gain value for internally waste gated turbos from Blitz is 5-15. I have mine set at 15 (along with a lot of other users I know) and the boost comes on strong. The 4 channels are just user presets. Set them to whatever you like for daily driving to track. I really only use two of them. The ratio is a percentage of the max output pressure your solenoid reads from your turbo. With the ratio set at 100 you should see 18-24psi depending on gear load, conditions, and of course every Supra is different. Obviously single owners will have different percentages as their turbos can push more then the stockers. I see 18 psi on average with a set ratio of 76 and daily drive at 48 seeing around 14 psi. Here is a recent, similar thread.

http://supraforums.com/forum/showthread.php?t=273497
 
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Will work for Supra parts
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Discussion Starter #7
Ahh, I see. So basically with a ratio of 30, it's quite possible I'm not boosting to my limiter's setting of 1.00 kg/cm2 or about 14 psi. I didn't hit overboost, I know that much. The display never went red, nor did it give the warning beep. I looked at the boost controller when I could, but I don't remember it hitting 1.00. The car moved pretty good at that setting, but it didn't really feel like 14 psi. Either the powerband is really linear and smooth with these Supras, or my car still has some more left in it because I'm not hitting the limiter. :D Once I get my gauges I will be ready to play with the settings more.

Thanks for the help guys.
 

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If you leave it to only "warn" showing on the display, it will not go off. It has to be set to "peak warn" showing on the display to set the limiter off. For example, look at this pic:





If you noticed the peak warn is showing on the display, you have to press the volume nob twice or until it shows up.
 
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Yes you are correct though you prob arent even hitting one bar at that setting of 30. I rarely ever use the low settings, cause its pointless, haha. I think my gain is around 20, and I do hit the limiter every so often. I dont think it makes much of a difference above 75 or so though. Certainly doesnt seem like it does.

I have my limiter at about 1.4bar. I usually dont hit that though. I think you should be good at 1.2, nice mostly safe setting. :D

Alex
 

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Discussion Starter #11
Awesome. I appreciate the links and the help guys. Up till now all my boost controller experience was with manual valves and the lack of a manual wasn't helping either. :D
 

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holy crap... your gain is set at 100 and you dont have spikes?


I checked it, 100% on the gain. I run up to 24 psi and it's externally wastegated so maybe that makes a difference. No spike problems. The wastegate reacts quickly.
 

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Discussion Starter #13
Hey guys,

Just wanted to say thanks again for the help in understanding my DSBC! I took my Supra out for a drive today to dail it in a little better and to see what kind of boost I was hitting. Well as it turns out with my ratio set at .30, my Supra was producing about 9 psi. Less then stock! :D

Believe me, the car ran great at that setting, but I was expecting a little harder shove in the back, hence I started this thread on the settings. So today I got some free time and I ran up the ratio a little at a time. My limiter is still set 1.00 or 14 psi. With a setting of 40, then 45, I'm now getting a solid 11.5 - 12 psi. And holy smokes, does the Supra move!!! :D I can't believe there is still more to play with! Just for grins I selected a ratio programmed already in the BC which was set at a ratio of 60. Not even going to WOT in 2nd gear the car just pulled so dang hard! I tried it again in 3rd and I hit my limiter (beep beep). Of course the BC backed the boost down and I also backed out of it. Checked my peak warn and it flashed a 1.00 or 14.2 psi.

All I can say is wow. Any BPU Supra at 12 psi is fast. I can't wait to get my gauges (boost and wideband O2) so I can play a little more at 14 psi and then maybe 18 psi. I cannot fathom the shove in the back you guys get at 18 psi, and more with big single turbos! Yikes! I cannot wipe the smile of my face at a mere 12 psi. :D
 

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its a slow auto...
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supra400hptt said:
holy crap... your gain is set at 100 and you dont have spikes?


I checked it, 100% on the gain. I run up to 24 psi and it's externally wastegated so maybe that makes a difference. No spike problems. The wastegate reacts quickly.

well then.. i'll have to play with mine and see what it does.. i have an external gate too(hks) and my gain is around 20-24 right now...

jay
 

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its a slow auto...
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Espeefan said:
Hey guys,

Just wanted to say thanks again for the help in understanding my DSBC! I took my Supra out for a drive today to dail it in a little better and to see what kind of boost I was hitting. Well as it turns out with my ratio set at .30, my Supra was producing about 9 psi. Less then stock! :D

Believe me, the car ran great at that setting, but I was expecting a little harder shove in the back, hence I started this thread on the settings. So today I got some free time and I ran up the ratio a little at a time. My limiter is still set 1.00 or 14 psi. With a setting of 40, then 45, I'm now getting a solid 11.5 - 12 psi. And holy smokes, does the Supra move!!! :D I can't believe there is still more to play with! Just for grins I selected a ratio programmed already in the BC which was set at a ratio of 60. Not even going to WOT in 2nd gear the car just pulled so dang hard! I tried it again in 3rd and I hit my limiter (beep beep). Of course the BC backed the boost down and I also backed out of it. Checked my peak warn and it flashed a 1.00 or 14.2 psi.

All I can say is wow. Any BPU Supra at 12 psi is fast. I can't wait to get my gauges (boost and wideband O2) so I can play a little more at 14 psi and then maybe 18 psi. I cannot fathom the shove in the back you guys get at 18 psi, and more with big single turbos! Yikes! I cannot wipe the smile of my face at a mere 12 psi. :D

hehe, yeah the car feals like another car when you jump from12-14 to 20psi :bigthumb: good luck with it.. my car with the 67mm turbo feels nothing like it did on stock twins, even at 13psi on the single,forget about 20 plus psi..

jay
 
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