Smoking tire review of super clean single turbo FD
Hi
Joined: Aug 2004
Posts: 106
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From: Rochester, MN
Just in case people didn't catch the previous video/thread:
https://www.rx7club.com/3rd-gen-gene...tuned-1055304/
https://www.rx7club.com/3rd-gen-gene...tuned-1055304/
Originally Posted by lOOkatme
My efr 8374 IWG surges like that at partial throttle as well.
Mine occurs at part throttle part boost areas, its when I modulate the throttle that the turbo doesn't like it. I think what is happening is the BOV isn't releasing pressure and the pressure backs up in the intercooler tract all the way back to the turbo, either that or the turbo is running out of its efficiency range?
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I believe it is the actual 8374 surging, the 7670 doesn't do it so that eliminates the BOV right?
7670 just straight whistles (spool) or sighs (BOV) all the time on throttle or part throttle, no gurgling or chuckling.
--------------
When I watched that vid with audio with headphones I realized how much more responsive my 7670 is than that 8374.
With my 7670 the turbo was whistling away spooling any time your foot was not completely off the gas pedal. You never had an engine sound without a whistle in the background- even lightly free revving to match rpms shifting. You got about 5psi boost in neutral free revving to moderate rpm (like stock twins).
Downside to the 7670, running over 17-20psi boost the boost/torque drops off at high rpm so you lose that loves to rev rotary feel and lose peak power compared to 8374.
With that 8374 at low rpm cruise you can actually hear the engine load pick-up (get louder) and then the turbo whistle come in a fraction of a second later. You can cruise without a constant whistle (actually pretty nice in a street car right!).
I am not criticizing either turbo, just observing differences because despite their size differences the turbos look so close in the low rpm on a dyno graph.
Also, intake and exhaust sizing/restriction will have an effect on turbo response on either turbo (but also don't show up on a dyno).
7670 just straight whistles (spool) or sighs (BOV) all the time on throttle or part throttle, no gurgling or chuckling.
--------------
When I watched that vid with audio with headphones I realized how much more responsive my 7670 is than that 8374.
With my 7670 the turbo was whistling away spooling any time your foot was not completely off the gas pedal. You never had an engine sound without a whistle in the background- even lightly free revving to match rpms shifting. You got about 5psi boost in neutral free revving to moderate rpm (like stock twins).
Downside to the 7670, running over 17-20psi boost the boost/torque drops off at high rpm so you lose that loves to rev rotary feel and lose peak power compared to 8374.
With that 8374 at low rpm cruise you can actually hear the engine load pick-up (get louder) and then the turbo whistle come in a fraction of a second later. You can cruise without a constant whistle (actually pretty nice in a street car right!).
I am not criticizing either turbo, just observing differences because despite their size differences the turbos look so close in the low rpm on a dyno graph.
Also, intake and exhaust sizing/restriction will have an effect on turbo response on either turbo (but also don't show up on a dyno).
I believe it is the actual 8374 surging, the 7670 doesn't do it so that eliminates the BOV right?
7670 just straight whistles (spool) or sighs (BOV) all the time on throttle or part throttle, no gurgling or chuckling.
--------------
When I watched that vid with audio with headphones I realized how much more responsive my 7670 is than that 8374.
With my 7670 the turbo was whistling away spooling any time your foot was not completely off the gas pedal. You never had an engine sound without a whistle in the background- even lightly free revving to match rpms shifting. You got about 5psi boost in neutral free revving to moderate rpm (like stock twins).
Downside to the 7670, running over 17-20psi boost the boost/torque drops off at high rpm so you lose that loves to rev rotary feel and lose peak power compared to 8374.
With that 8374 at low rpm cruise you can actually hear the engine load pick-up (get louder) and then the turbo whistle come in a fraction of a second later. You can cruise without a constant whistle (actually pretty nice in a street car right!).
I am not criticizing either turbo, just observing differences because despite their size differences the turbos look so close in the low rpm on a dyno graph.
Also, intake and exhaust sizing/restriction will have an effect on turbo response on either turbo (but also don't show up on a dyno).
7670 just straight whistles (spool) or sighs (BOV) all the time on throttle or part throttle, no gurgling or chuckling.
--------------
When I watched that vid with audio with headphones I realized how much more responsive my 7670 is than that 8374.
With my 7670 the turbo was whistling away spooling any time your foot was not completely off the gas pedal. You never had an engine sound without a whistle in the background- even lightly free revving to match rpms shifting. You got about 5psi boost in neutral free revving to moderate rpm (like stock twins).
Downside to the 7670, running over 17-20psi boost the boost/torque drops off at high rpm so you lose that loves to rev rotary feel and lose peak power compared to 8374.
With that 8374 at low rpm cruise you can actually hear the engine load pick-up (get louder) and then the turbo whistle come in a fraction of a second later. You can cruise without a constant whistle (actually pretty nice in a street car right!).
I am not criticizing either turbo, just observing differences because despite their size differences the turbos look so close in the low rpm on a dyno graph.
Also, intake and exhaust sizing/restriction will have an effect on turbo response on either turbo (but also don't show up on a dyno).
The 7670 is in fact quicker to spool up and it may give a more favorable power delivery for a short course/time attack/autoX type course. It very well could be the turbo surging, I agree. My old GT3574R would do the same thing as well just not as pronounced. With the lighter wheels it almost wants to stop the turbo. I also get some surging in 5th gear large load low rpms the turbo can surge.
While watching a lot of time trail small course stuff, looks to me that large displacement engines will be tough beat. I think the torque advantage and lack of shifting (tall gears) give these engines a huge advantage. If I were to compete in these types of course you need high spring rates for fast transition and small turbo's to simulate a large displacement engine to get more/wider power band.
on the street softer rate springs and bigger turbo's do very well with long sweeping corners. Much different set up. I also think the linear NA power is better on tight small autoX courses, There is a guy with a Miata who does very well but still cannot beat the larger displacement big money cars.
As soon as we moved to the half bridge on Shawn's IWG 8374 the surging went away completely.
The original thread for that video was really interesting - the car belongs to one of the members on here. Does anyone have any other recommendations for similar high quality "semi-professional" youtube videos on the FD3?
Does anyone have any other recommendations for similar high quality "semi-professional" youtube videos on the FD3?
The Option2/ Video Option/ Hot Version count as semi professional
A group of retired and active race car drivers reviewing tuner cars.
I like the Gunsai SportsCycle track "Touge Challenge" segment since it focuses on streetable tuned cars and well, a stock sequential twins FD is still at the top.
Example
The Option2/ Video Option/ Hot Version count as semi professional
A group of retired and active race car drivers reviewing tuner cars.
I like the Gunsai SportsCycle track "Touge Challenge" segment since it focuses on streetable tuned cars and well, a stock sequential twins FD is still at the top.
Example
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May 20, 2002 07:34 PM