Jump to content
SAU Community

Please Help Me Diagnose My Dyno Chart

blackprincegts

By blackprincegts,
in Engines & Forced Induction

 Share

Recommended Posts

blackprincegts Collaborator

blackprincegts

Posted
Posted

hey...

I had my GTS r32 dynoed about 1 1/2 years ago, mods were a 2 1/4inch exhaust and a k&n pod (which is actually on an adapter thats about 1 -2mm smaller that the afm opening) with no cold air induction..

Heres my dyno chart, i had lost it for quite some time but found it the other day and started to have a really good look at it.

rb20de dyno

As you can probably tell by the speed it would have been done in 3rd gear which isnt right i know but...

I noticed that my peak power was reached at about 5700-5800rpm, the power then seems to drop off significantly after this, thats what i find quite odd. This engine stock should be producing its peak power at 6100or something like that but by the time iv reached those revs the powers already dropping off quite quickly.

Is there anything that anyone can suggest that could be going wrong there to make the engine stop producing power where it does?? Is it possible that the dyno reading was setup wrong therefore meaning that the speed shown on the graph does not match that of the revs that i have plotted on there?.

Its hard to say for sure but when the car was new to me it used to come on power at about 5000rpm and pretty much maintain that pull right through to about 6500 and only slightly drop off by the time i would shift at 7000rpm. Now the car seems to all ova sudden go quite hard as soon as i huit about 5grand but die off again quite drammatically after this point.

In a way im kind of hopeing theres something only simple wrong so meaning that when fixed the motor should continue to make more power right up untill atleast where it makes it stock from the factory.Im wondering if it is my pod setup though thats sent things a bit wierd.. i should really do it properly and mount it down in the front bar and use the right adapter for it..i know people that have gained about 2.5 to 3kw's at the wheels by doing this..( a neck breaking difference i know, LOL :yes: )

Any input appreciated... cheers!

Eug Grand Master

Eug

Posted
Posted

have your AFRs cleaned up, it won't entirely solve your problem - but it is a little over the shop. do you have an SAFC, ecu, chip or anything?

as to your power issue, the graph looks fine to me - but you've had history with the car, so just start troubleshooting. have a fiddle with your pod filter, service the car, look into timing advance/retard, etc.

that said - the dyno always feels/drives differently to when your actually on the street, so don't take it as gospel. does it "feel" slower to you?

blackprincegts Collaborator

blackprincegts

Posted
  • Author
Posted

Well the cars just clocked over 149 000 km's and it would appear to be the factory standard cat going by what it looked like when i got the got. i doubt the jap owner would hav changed it in the 90 000kms he they had the car for.. You think my cat could be killing off some of the power?

nah its the stock ecu etc... iv been told of someone that can do a remap for really cheap for me that might help things along a bit..

i just spent a few hours re-drilling and cleaning up my pod adapter and I THINK the car seems to be pulling a bit harder up top, but id say the biggest thing that has changed is the engine seems to respond a bit better now iv mucked around with it a bit.

Cubes, so you think its normal that my peak power is coming on before what nissan quote for my motor and already start dropping off hardcore by time it reaches that point, i would have thought that having a pod and exhaust would have pushed it up further if anything..

cheers

Fixxxer Community Regular

Fixxxer

Posted
Posted

The RPM data on the bottom of the sheet seems to jump around everywhere. Speed versus RPM will remain constant in one gear. From what I can make out, your RPM jumps from as little as 600rpm per 15km/h increase to 1000rpm per 15km/h increase in speed. This can not happen. Until you can find out your actual RPM I wouldn't bother trying to work out anything, it looks like a normal dynograph to me.

Fixxxer

Sean'O Proficient

Sean'O

Posted
Posted

Hey mate,

I've got an r-32 GTS too, I can't really help you with the graph business caus I don't have a great deal of knowledge when it comes to dyno's, but I noticed you said about mounting the Pod in your front bar, how do you do that without cutting into your chassis?

I have had a good look and I can't seem to find any route to cold air?

Sorry for the off topic ness lol

mad082 Grand Master

mad082

Posted
Posted

your graph doesn't look that bad for a stock ecu. i'd say that is pretty close to what it should make.

when i had a SSS pulsar (natro sr20) i put it on the dyno and got a similar readout. graph was a little bit more stagered than that. and got about 2kw less.

then my last car before my skyline had a dead smooth curve. no rough spots. the dyno guy said it was one of the smoothest curves he had ever seen. it was a '00 magna with a stock ecu and full exhaust.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • Randhj
      R34 4 door indicator and horn issue

      By Randhj · Posted

      Thanks, I removed the fuse and the relay from the car and made my own circuit with them to test them with a test bulb.  I will look for the wiring diagram and go from there.
    • Milkmun
      The FD RX7 is the best looking 90's JDM car

      By Milkmun · Posted

      Jdm DC2R is also nice for a FF car compared to the regular hatches of the time.
    • PranK
      The FD RX7 is the best looking 90's JDM car

      By PranK · Posted

      Gotta admit, I love the 20b Cosmo.
    • joshuaho96
      Nismo Super Coppermix Twin and R33 GTR transmission replacement

      By joshuaho96 · Posted

      Now that the break-in period for both clutch and transmission is nearly over I'd like to give some tips before I forget about everything that happened, also for anyone searching up how to do this job in the future: You will need at least 6 ton jack stands at full extension. I would go as far as to say maybe consider 12 ton jack stands because the height of the transmission + the Harbor Freight hydraulic platform-style transmission jack was enough that it was an absolute PITA getting the transmission out from under the car and back in. The top edge of the bellhousing wants to contact the subframe and oil pan and if you're doing this on the floor forget about trying to lift this transmission off the ground and onto a transmission jack from under the car. Also do not try to use a scissor jack transmission lift. You have to rotate the damn thing in-place on the transmission jack which is hard enough with an adjustable platform and a transmission cradle that will mostly keep the transmission from rolling off the jack but on a scissor lift with a tiny non-adjustable platform? Forget it. Use penetrating oil on the driveshaft bolts. I highly recommend getting a thin 6 point combination (box end + open end) wrench for both the rear driveshaft and front driveshaft and a wrench extension. These bolts are on tight with very little space to work with and those two things together made a massive difference. Even a high torque impact wrench is just the wrong tool for the job here and didn't do what I needed it to do. If your starter bolts aren't seized in place for whatever reason you can in fact snake in a 3/8 inch ratchet + 6 point standard chrome socket up in there and "just" remove the bolts for the starter. Or at least I could. It is entirely by feel, you can barely fit it in, you can barely turn the stupid ratchet, but it is possible. Pull the front pipe/downpipe before you attempt to remove the transmission. In theory you don't have to, in practice just do it.  When pulling the transmission on the way out you don't have to undo all the bolts holding the rear driveshaft to the chassis like the center support bearing and the rear tunnel reinforcement bar but putting the transmission back in I highly recommend doing this because it will let you raise the transmission without constantly dealing with the driveshaft interfering in one way or another. I undid the bottom of the engine mount but I honestly don't know that it helped anything. If you do this make sure you put a towel on the back of the valve cover to keep the engine from smashing all the pipes on the firewall. Once the transmission has been pulled back far enough to clear the dowels you need to twist it in place clockwise if you're sitting behind the transmission. This will rotate the starter down towards the ground. The starter bump seems like it might clear if you twist the transmission the other way but it definitely won't. I have scraped the shit out of my transmission tunnel trying so learn from my mistake. You will need a center punch and an appropriate size drill bit and screw to pull the rear main seal. Then use vice grips and preferably a slide hammer attachment for those vice grips to yank the seal out. Do not let the drill or screw contact any part of the crank and clean the engine carefully after removing the seal to avoid getting metal fragments into the engine. I used a Slide Hammer and Bearing Puller Set, 5 Piece from Harbor Freight to pull the old pilot bearing. The "wet paper towel" trick sucked and just got dirty clutch water everywhere. Buy the tool or borrow it from a friend and save yourself the pain. It comes right out. Mine was very worn compared to the new one and it was starting to show cracks. Soak it in engine oil for a day in case yours has lost all of the oil to the plastic bag it comes in. You may be tempted to get the Nismo aftermarket pilot bearing but local mechanics have told me that they fail prematurely and if they do fail they do far more damage than a failed OEM pilot bushing. I mentioned this before but the Super Coppermix Twin clutch friction disks are in fact directional. The subtle coning of the fingers in both cases should be facing towards the center of the hub. So the coning on the rearmost disk closest to the pressure plate should go towards the engine, and the one closest to the flywheel should be flipped the other way. Otherwise when you torque down the pressure plate it will be warped and if you attempt to drive it like this it will make a very nasty grinding noise. Also, there is in fact an orientation to the washers for the pressure plate if you don't want to damage the anodizing. Rounded side of the washer faces the pressure plate. The flat side faces the bolt head. Pulling the transmission from the transfer case you need to be extremely careful with the shift cover plate. This part is discontinued. Try your best to avoid damaging the mating surfaces or breaking the pry points. I used a dead blow rubber hammer after removing the bolts to smack it sideways to slide it off the RTV the previous mechanic applied. I recommend using gasket dressing on the OEM paper gasket to try and keep the ATF from leaking out of that surface which seems to be a perpetual problem. Undoing the shifter rod end is an absolute PITA. Get a set of roll pin punches. Those are mandatory for this. Also I strongly, strongly recommend getting a palm nailer that will fit your roll pin punch. Also, put a clean (emphasis on clean) towel wrapped around the back end of the roll pin to keep it from shooting into the transfer case so you can spend a good hour or two with a magnet on a stick getting it out. Do not damage the shifter rod end either because those are discontinued as well. Do not use aftermarket flywheel bolts. Or if you do, make sure they are exactly the same dimensions as OEM before you go to install them. I have seen people mention that they got the wrong bolts and it meant having to do the job again. High torque impact wrench makes removal easy. I used some combination of a pry bar and flathead screwdriver to keep the flywheel from turning but consider just buying a proper flywheel lock instead. Just buy the OS Giken clutch alignment tool from RHDJapan. I hated the plastic alignment tool and you will never be confident this thing will work as intended. Don't forget to install the Nismo provided clutch fork boot. Otherwise it will make unearthly noises when you press the clutch pedal as it says on the little installation sheet in Japanese. Also, on both initial disassembly and assembly you must follow torque sequence for the pressure plate bolts. For some reason the Nismo directions tell you to put in the smaller 3 bolts last. I would not do this. Fully insert and thread those bolts to the end first, then tighten the other larger pressure plate bolts according to torque sequence. Then at the end you can also torque these 3 smaller bolts. Doing it the other way can cause these bolts to bind and the whole thing won't fit as it should. Hope this helps someone out there.
    • PLYNX
      The FD RX7 is the best looking 90's JDM car

      By PLYNX · Posted

      Of the 90s ! !
×
×
  • Create New...