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Had my car dyno'd by Autotech (ACT) last week. I feel it was a good result and was hoping for some comment. Dyno not run in shootout mode. Air temp ~14c. Blue line is std boost, red peak ~8psi.

My car has what follows,

FMIC ~ 500x300x65

3" from dump back exhaust

POD

Manual boost via bleed

Splitfire coils (not really important I know)

500hp Bosch Fuel pump

Everything else otherwise std.

Problem is the car still feels very flat under 5000rpm as the graph indicates. Also I couldn't wind boost higher than 8psi due to a misfring issue that has yet to be sorted. (btw plugs 'should' be fine. Plantium's gapped to .8mm). I believe it to be the ignitor module, or coils.

Just wondering if anyone had any comment about the powercurve re flat feelin under 5000rpm (100kph).

Thanks!!

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Give it some boost, that should fix your midrange problems , but you'll need to address your missfiring problems first.

I was only getting a peak of 15rwkw between 9 and 13 psi, but midrange was huge.

Hey Robo,

Just wondering if you have any dyno sheets I could compare against?

I plan to give it some more boost, but defintley need to fix the annoying missfiring issues.

Thanks

Maxium - what motor are you running in the 180sx??

I've had mine up on AutoTechs dyno a few times so we could have a good gauge etc...

If your running a RB25det, make sure the variable inlet cam is working cause that's the first thing I thought it might be.

I've got my dyno print out of the run I did on AutoTech's dyno, I'll try and find it for you.

J

Hey Jay,

Sorry I should have put it in. It's a RB25det. Actually might sound weird but I think I already have yours! I did a search awhile ago for dyno runs and got a collection of guys posts and I'm pretty sure I found yours too. from the 28/1/04?

I noticed your mid range is heaps beefier than mine but top end is same ish (might be other variables of course). Did you end up getting some kind of fuel controller? Looks like from the graph you could get massive gains from tuning the AFR.

Found the dyno sheets;

Green line was the new result, red line was what it was like before the cam gear went in....

Car was a R33 GTS-t. Mods where 12-9psi (see the sheet !), panel filter, FMIC, turbo back 3 inch exhaust, cam gear set at 3 degrees retard.

The day was pushing 33 degrees too :rolleyes:

J

Cool (didn't realise you squeezed a post in :rolleyes: ),

Yeah, I had plans on getting a re-chipped ECU for it so I could run more timing and trim up the A/F ratio's, but I had a accident 2-3 weeks ago and I'm not sure if I'll get the car back (could be a write off !)....

I also had plans on getting a HKS wastegate actuator cause the boost drops right off up top..

I'd double check to see if your variable cam is working, then check for wastegate creep (doughtful..) but worth a try.

J

Just found this dyno run that you might find interesting....

It's back to back runs with the VCT working, and then with the VCT not working.

Top line is with it working, and the bottom is with it not. You can see how much of a difference the variable cam timing makes to the low/mid range :rolleyes:

Just ignore the A/F ratios on this one, after this we found that the sensor wasn't in the exhaust all the way :)

J

Hey Jay,

Thanks for your effort! Appreciated.

Damn hope you came out of the accident alright! What's the story behind that?

From what you've told me i'm thinking the VCT could be dud. The only other thing I was thinking of was base timing but I'm pretty sure its ok.

The 2nd dyno sheet has a far meatier low-mid range as I would have expected from a rb25, what I don't have! A practical example, I was going through a sweeping left into a form onelane when some chump in a VL (na) tried to beat me to it. After going full throttle it wasent until I hit top end did I reel and pass him. Has is that dyno of std boost?

I'll get my mechanic to check out the VCT asap but is there any easy checks I could do like unplug and if its no change then thats the problem?

The otherthing I thought it might be is related to the missfiring but that has only been occuring the last few weeks with the sluggishness ever since day 1.

Both those dyno sheets where done at the same boost levels - ie. 12psi dropping to about 9.7 up higher.. I was also running about 17 degrees base timing for those runs, but strangely, adjusting it from 15 to 17 made almost no difference !! Not sure why...

Yepp, everyone came out of the accident OK, just the cars didn't :thumbsup:

One thing that may make a difference, but maybe not, is that the bleed valve I was using has an anti wastegate creep valve built in. Not sure if it'd make a difference though...

For the VCT, just do a run on the dyno with it plugged in, and then do a run with it unplugged, you'll see the difference straight away. Another way is to check with a mutli meter to see if it's getting power to the plug, but then maybe the actual solinoid might be stuffed as well.. :)

The only other thing I can think of is maybe you've got a faulty knock sensor or something. Try running the diags on the ECU and see if any faults come up...

J

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