Single Turbo RX-7's Questions about all aspects of single turbo setups.

Went single and lost horsepower

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Old May 23, 2013 | 10:48 PM
  #126  
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Where are you taking your boost pressure from?
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Old May 23, 2013 | 11:01 PM
  #127  
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Originally Posted by lOOkatme
Where are you taking your boost pressure from?
UIM. I have a legit DEFI gauge. Its rock solid at 15psi.
PFC is saying 1.00 kg/cm^2
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Old May 24, 2013 | 09:06 AM
  #128  
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Originally Posted by ArmenMAxx
UIM. I have a legit DEFI gauge. Its rock solid at 15psi.
PFC is saying 1.00 kg/cm^2
Touching this, i have a weird situation. My boost gauge is reading 9/10psi per spring pressure and PFC is saying 1.00/1.15 boost and im also reading from UIM and have tried 2 different gauges. Any suggestions for this?

Sorry for the thread jacking.
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Old May 24, 2013 | 10:34 AM
  #129  
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Originally Posted by ArmenMAxx
UIM. I have a legit DEFI gauge. Its rock solid at 15psi.
PFC is saying 1.00 kg/cm^2
ok, the reason I ask is some people measure/control boost on the hot side of the turbo/intercooler and have a pressure loss through the intercooler and are not taking that into account. You are doing it the right way by using the UIM to measure your boost to ensure the engine is seeing that pressure amount.
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Old Jul 5, 2013 | 10:46 AM
  #130  
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Any updates?

As I see it, you don't have restriction, your fuel system is flowing certain amount of fuel and you have resulting lambda number from which you can calculate airflow. Air/fuel also isn't that rich to loose so much power.

Poor reaction for advance settings would indicate problem with leading side of ignition, it doesn't have to break-up and it can be issue.
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Old Jul 5, 2013 | 11:54 AM
  #131  
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you could be running on trailings... have you tested you coils?
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Old Jul 5, 2013 | 01:10 PM
  #132  
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Originally Posted by Liborek
Any updates?

As I see it, you don't have restriction, your fuel system is flowing certain amount of fuel and you have resulting lambda number from which you can calculate airflow. Air/fuel also isn't that rich to loose so much power.

Poor reaction for advance settings would indicate problem with leading side of ignition, it doesn't have to break-up and it can be issue.

Originally Posted by neit_jnf
you could be running on trailings... have you tested you coils?
I have been just driving and tracking the car. I kind of got sick of trying to figure out whats causing my lower HP #'s but I am going to continue working on it this summer.

The issue with the leading coil makes sense. When we were tuning on the dyno and adding/taking away leading I remember there being very little difference in HP. Even if the difference was great as 4/5 units. Maybe this was a symptom of a bad leading coil.

Aside from the leading coil my only other thoughts are that my HKS cast/RB dual exhaust combined are creating a restriction. However when you look at others using components, most have had no issues hitting efficient #'s.

I raced a ~500whp Supra and lightly inched on it. Maybe both dyno jets I've used were off? lol Ill post a vid of some pulls on the hwy and maybe try to calculate 60-100mph times.
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Old Jul 5, 2013 | 11:59 PM
  #133  
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I'd check your coils/twin power setup. I know a lot of folks swear by them howerver I've seen too many stock coils eat themselves after 20ish years of heat cycles. On a side note whats your dwell set to? IIRC the PFC is kind of dumb in that it displays dwell time degrees rather than on time. It's been a while since I've tuned a PFC though so I could be transposing it onto another ECU.
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Old Jul 6, 2013 | 06:12 PM
  #134  
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Originally Posted by dguy
I'd check your coils/twin power setup. I know a lot of folks swear by them howerver I've seen too many stock coils eat themselves after 20ish years of heat cycles. On a side note whats your dwell set to? IIRC the PFC is kind of dumb in that it displays dwell time degrees rather than on time. It's been a while since I've tuned a PFC though so I could be transposing it onto another ECU.
I am planning on checking my coils asap. Most people who have failing coils do experience obvious effects, but eitherway im going to check them anyways.

Can you help explain to me what the dwell timing degree is? Ive never really heard of it.
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Old Jul 6, 2013 | 08:32 PM
  #135  
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Leave the dwell time alone, it doesn't matter. (assuming its stock)

thewird
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Old Jul 6, 2013 | 10:26 PM
  #136  
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Originally Posted by thewird
Leave the dwell time alone, it doesn't matter. (assuming its stock)

thewird
Exactly. I was under the impression that he had started the setup with a very conservative by someone else. I've seen some wacky things come across my desk regarding dwell and timing to create a 'safe' environment inside an engine.
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Old Jul 6, 2013 | 11:18 PM
  #137  
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99.999999999% of people don't touch the dwell map on a PFC. There is absolutely no reason to unless your running aftermarket coils like AEM. And pretty much almost those same amount of people don't even understand how it works on the PFC.

You can thank Chris Ludwig for testing it and actually figuring it out AND sharing that information with the community. He even provided an excel calculator to convert to normal ms numbers.

thewird
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Old Jul 7, 2013 | 07:58 AM
  #138  
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if you are using the the HKS twin power, it is unaffected by dwell time anyway, since it is CDI and just looking for a trigger from the ECU. i doubt ignition would cause such low power output, but you could try going back to the factory inductive ignitor
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Old Jul 7, 2013 | 12:24 PM
  #139  
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99.999999999% of people don't touch the dwell map on a PFC. There is absolutely no reason to unless your running aftermarket coils like AEM. And pretty much almost those same amount of people don't even understand how it works on the PFC.

You can thank Chris Ludwig for testing it and actually figuring it out AND sharing that information with the community. He even provided an excel calculator to convert to normal ms numbers.

thewird
Sorry, wasn't trying to spark any sort of off topic debate, however I've seen two instances where someone has fiddled with dwell only to either forget to reset it back to normal or thought they were doing a good thing. Unfortunately Chris Ludwig's guide wasn't available at the time so I spent a good long while figuring out the who Degree/MS relationship. Didn't make sense to me until it just...did.

Anyway, its an easy thing to check and it wouldn't hurt. I'm NOT endorsing changing the dwell timing from stock however.

Originally Posted by gxl90rx7
if you are using the the HKS twin power, it is unaffected by dwell time anyway, since it is CDI and just looking for a trigger from the ECU. i doubt ignition would cause such low power output, but you could try going back to the factory inductive ignitor
Half true, the later universal Twin Powers (2007?) and on are a hacked CDI however the earlier models, which I've mostly seen, are just dwell amplifiers. They still work well and are a very clean install though.
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Old Jul 8, 2013 | 01:38 AM
  #140  
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lol 10.7 AFR pm 15psi.......

Tuner showing no confidence with rotary tuning?
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Old Jul 8, 2013 | 02:14 PM
  #141  
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My coils seem to be fine. Just checked and the ohm resistance is within spec.
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Old Jul 8, 2013 | 02:25 PM
  #142  
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is the HKS TP working correctly? I had two units that just quit working after some time and returning to stock fixed the problem
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Old Jul 8, 2013 | 03:35 PM
  #143  
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Originally Posted by ArmenMAxx
My coils seem to be fine. Just checked and the ohm resistance is within spec.
You need an oscilloscope to check coils, not just an ohm check.

I would move the AEM coils, and a direct fire setup if you wanted to toss money at the this.. It would help regardless...
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Old Jul 8, 2013 | 04:48 PM
  #144  
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I still dont get why you are running so rich?
Did you try lean it off a few points to see if it picked up? Bring it back to 11.50s? See if it responds? If it is an ignition issue it will respond to the leaner afr.
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Old Jul 8, 2013 | 05:40 PM
  #145  
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My guess would be your timing is off. This could be confirmed with high EGTs, but if I remember correctly you aren't logging that correct? I know with my FC when I found that my CAS was off one tooth I picked up a lot of power with the butt dyno.
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Old Jul 8, 2013 | 09:31 PM
  #146  
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Originally Posted by rx7 SE
My guess would be your timing is off. This could be confirmed with high EGTs, but if I remember correctly you aren't logging that correct? I know with my FC when I found that my CAS was off one tooth I picked up a lot of power with the butt dyno.
You know what, I dont think I have every checked the timing on my car (manually) with a timing light. Thats is def on the to do list. I know my timing via PFC is as aggressive as I should go but maybe its all off.

Originally Posted by rx72c
I still dont get why you are running so rich?
Did you try lean it off a few points to see if it picked up? Bring it back to 11.50s? See if it responds? If it is an ignition issue it will respond to the leaner afr.
I am actually running 11.2-11.3 now. Thats the leanest I am going to go just to keep that margin of safety. I know I can go 11.5 or more but it wont really gain more than 2-5whp doing so. I didnt feel a diff when we went from 11.0 to 11.3 at all. Just slightly better spool.

Originally Posted by neit_jnf
is the HKS TP working correctly? I had two units that just quit working after some time and returning to stock fixed the problem
I'm pretty sure they are working properly. Without the TP my car had breakup in the upper rpm's and now its fine.

I would move the AEM coils, and a direct fire setup if you wanted to toss money at the this.. It would help regardless...[/QUOTE]

Sooner than later I will be moving up to the AEM coil setup. Prob next Christmas time but for now I am just trying to enjoy her while its all together and dump the extra cash on track days. You are right tho, ohm readings only give a partial diagnosis of the coil condition.
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Old Jul 8, 2013 | 09:35 PM
  #147  
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Originally Posted by Turblown
You need an oscilloscope to check coils, not just an ohm check.

I would move the AEM coils, and a direct fire setup if you wanted to toss money at the this.. It would help regardless...
I am def going to get the AEM coils sooner than later but for now, as you would prob agree, I am just going to save the $$$ and use it for track days (which is really draining the bank account lol) Prob Christmas time I will do a few changes to the car such as new coils, bigger exahust, and MAYBE one of your nice manifolds)

The car really feels good now. Aside from the lower HP #s it powerband feels good and is smooth. I really need to get my hands on a nice camera so I can post some videos in this thread.
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Old Jul 8, 2013 | 11:32 PM
  #148  
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Checking timing on an FD is a waste of time. It's not like the FC where u have to set it. It's a fixed pair of sensors so nothing can be adjusted.

thewird
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Old Jul 9, 2013 | 05:04 PM
  #149  
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Originally Posted by thewird
Checking timing on an FD is a waste of time. It's not like the FC where u have to set it. It's a fixed pair of sensors so nothing can be adjusted.

thewird
Wish I read this a bit earlier. Was looking at the cam sensors and was scratching my head as to how they adjust.
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Old Jul 9, 2013 | 08:52 PM
  #150  
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good thread, just finished it. did you ever make the videos of the pulls on the highway?
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