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My Motor feels much stronger and powerful at part throttle than at WOT.

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My Motor feels much stronger and powerful at part throttle than at WOT.

Old 09-04-18, 03:02 PM
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My Motor feels much stronger and powerful at part throttle than at WOT.

I always get more punch and wheelspin at say 60% throttle than WOT especially in 1st and 2nd gear. This is on my 66mm single turbo 13B. I suspect it is because I have secondary butterflies disabled and removed from the intake manifold.
Can someone confirm that this could be the the cause.
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Old 09-04-18, 03:04 PM
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Originally Posted by jetlude View Post
I always get more punch and wheelspin at say 60% throttle than WOT especially in 1st and 2nd gear. This is on my 66mm single turbo 13B. I suspect it is because I have secondary butterflies disabled and removed from the intake manifold.
Can someone confirm that this could be the the cause.
Doubt it. Sounds like you needz moar boost.
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Old 09-04-18, 04:55 PM
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I never had a big turbo, but I also removed the 2ndary throttle plates, synched the throttles to open together/all the way open (they don't stock) and ported my intake runner diameter too big as well.

I had the issue you describe where it pulled cleaner at low rpms giving it progressive throttle input and it was tuning issues. Once I had the tune all sorted it out it didn't "bog" no matter how fast you whacked the throttle open, but it was lots of little things in the tune and lots of time spent driving around in circles in big parking lots.

Another reason you could have this same issue is if the Wastegate boost reference line is taken off the intake manifold after the throttle body.
In this instance you would actually be running higher boost (measured between turbo outlet to throttle body) with the throttles partially closed. Basically, the pressure drop from the partially closed throttle body is negated if you put the wastegate boost reference line after the throttle body somewhat defeating the job of the throttle body in governing power output and definitely making the turbo boost higher at partial throttle.

If you have the wastegate boost reference line after the throttle body and like how it pulls at partial throttle, measure your boost between the turbo outlet and throttle body at partial throttle, move the wastegate boost reference line in front of the throttle body and turn the boost up to what you measured at partial throttle. Should pull the same at partial throttle then and much more at full throttle.
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Old 09-05-18, 02:44 PM
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Originally Posted by BLUE TII View Post
I never had a big turbo, but I also removed the 2ndary throttle plates, synched the throttles to open together/all the way open (they don't stock) and ported my intake runner diameter too big as well.

I had the issue you describe where it pulled cleaner at low rpms giving it progressive throttle input and it was tuning issues. Once I had the tune all sorted it out it didn't "bog" no matter how fast you whacked the throttle open, but it was lots of little things in the tune and lots of time spent driving around in circles in big parking lots.

Another reason you could have this same issue is if the Wastegate boost reference line is taken off the intake manifold after the throttle body.
In this instance you would actually be running higher boost (measured between turbo outlet to throttle body) with the throttles partially closed. Basically, the pressure drop from the partially closed throttle body is negated if you put the wastegate boost reference line after the throttle body somewhat defeating the job of the throttle body in governing power output and definitely making the turbo boost higher at partial throttle.

If you have the wastegate boost reference line after the throttle body and like how it pulls at partial throttle, measure your boost between the turbo outlet and throttle body at partial throttle, move the wastegate boost reference line in front of the throttle body and turn the boost up to what you measured at partial throttle. Should pull the same at partial throttle then and much more at full throttle.
Thanks for you reply. Don't get me wrong, the car runs well and I don't think this is tune related (self done). The car absolutely does not bog at all at WOT, in fact I think it pulls how it should. It just appears to pickup an extra 20 or so RWHP if I do about 60-70% throttle up to about 6000rpm instead of WOT right through. I was thinking it was one of the reasons mazda put these butterflies on the secondary runners to control the intake flow to keep the intake air velocity high.
Kind of what is spoken on in post 21 of this thread and video.

https://www.rx7club.com/single-turbo...eport-1128932/

You thoughts on this concept^^

Last edited by jetlude; 09-06-18 at 01:41 PM.
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Old 09-06-18, 10:48 AM
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Do you have any datalogs?

Do you have any kind of accelerometer to record the G forces?
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Old 09-06-18, 01:46 PM
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Originally Posted by arghx View Post
Do you have any datalogs?

Do you have any kind of accelerometer to record the G forces?
No accelerometer, only seat of the pants, but should have logs.
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Old 09-06-18, 06:06 PM
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The intake velocity thing makes sense to me, it a phenomenon I've experienced personally with various cars and bikes, again just subjectively on the butt-dyno. Its good practice to roll the throttle on with RPM anyway if you ask me.
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Old 09-06-18, 07:01 PM
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I've felt this sensation before and thought it had more at part throttle than full . When I actually did back to back logs on virtual dyno I found power was exactly the same . It's surprising how little difference there is betweeen part throttle and full throttle on a turboed car . Also ...what Blue t11 said ...put your boost reference pre throttle and you will get more precise throttle control .
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Old 09-06-18, 09:15 PM
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It's surprising how little difference there is betweeen part throttle and full throttle on a turboed car
When I had really big intake and exhaust ports in my engine the powerband had more to do with turbo rpm than throttle input.

Anything over ~25% throttle and over ~4,500rpm engine speed felt basically the same as whacking it open to full throttle. Which was alarming.

I just went to a more mild port on intake and exhaust and it solved this driveability issue (you need lots of throttle control when you are "racing" in a parking lot).

Didn't lose any peak power either since the little turbo was maxed out at 385rwhp on each set-up anyways.
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Old 09-07-18, 11:38 AM
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Intake velocity

Originally Posted by WANKfactor View Post
The intake velocity thing makes sense to me, it a phenomenon I've experienced personally with various cars and bikes, again just subjectively on the butt-dyno. Its good practice to roll the throttle on with RPM anyway if you ask me.
I'm definitely going to do more research on this. You guys can chime in with any other info on this topic you wish to share, or if you have any links to articles or write ups on this, rotary or not.

Last edited by jetlude; 09-07-18 at 11:42 AM.
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