Good at reading Dyno Graphs? Help me out...

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Feb 27, 2006 | 11:36 AM

Rizlam

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From: UK

Good at reading Dyno Graphs? Help me out...

Hi everyone from the UK

My car is in the process of being tuned, and has lost 30bhp from the top end:

This is a graph showing before and after.

Greeny/red pair is 'before'
Bright red line is 'after'.

I asked them to sort the 'hole' at 5000 rpm but now I have a strange dip at 6000 rpm - which means the max power has dropped 30 bhp (but only at the top end).

Spec... it's a Vortech Supercharger using the Split Second box. I'm happy to have that much smoother torque line at 5000 - 6000 rpm but what the hell is happening at 6K?

Any ideas what might be causing this? I've kept the car in the tuning shop while they try and investigate, and am curious to hear your thoughts too.

Here's a link to the full dynapack pdf - http://stephengrant.com/350z/images/dynapack270206.pdf

The AFM seems to dive into very rich territory at 6K as well. Does this mean I'm getting air starvation, perhaps?

Feb 27, 2006 | 03:30 PM

phunk

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belt slip?

whats with the torque reading almost 1500?

Feb 27, 2006 | 03:32 PM

97supratt

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From: Glendale California

Quote:

Originally Posted by phunk

belt slip?

whats with the torque reading almost 1500?

Thats one sick engine, I wonder what the bore is on that?

Feb 27, 2006 | 03:38 PM

booger

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From: council bluffs Ia.

you gained power and trq from 5000rpm to 6000rpm and then it drops off . My only guess would be that the tuner made a big jump in timing retard after 6000rpm and added a bunch of fuel . You go from 11.5 A/F to 10.5 A/F . Your boost looks like it gains all the way to redline . If the belt was slipping it would more than likely hold or drop off

Feb 27, 2006 | 03:40 PM

D350Z10

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it is hitting 1500 because that is uncorrected, are you auto it tend to do that. Corrected his torque is close to 350 I believe. About the loss in power, if no engine code or ses light, it has to do with your blower, check all the belts, boost leaks and other chit of that nature.

Feb 27, 2006 | 03:42 PM

booger

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From: council bluffs Ia.

Yeh whats with the trq numbers ???

Feb 27, 2006 | 03:45 PM

booger

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From: council bluffs Ia.

If you go to the link provided , you can see the boost chart . It gains all the way to redline . And the A/F chart shows a big drop off

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Feb 27, 2006 | 03:49 PM

Rizlam

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From: UK

Torque has not been normalised to ratio (4.6) - divide by that.

Any suggestions? I think we can discount belt slip.

Feb 27, 2006 | 04:01 PM

booger

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From: council bluffs Ia.

the stock Vortech timing map retards timing [1] degree at 5000...[2] at 5500 [4] at 6000 [8] at 6500 and [10] at 7000rpms . As soon as you pass [ say ] 6000rpm it starts to pull timing to 8 degree . The tuner may have lessened the timing being pulled at 5000 and 5500rpms and that increased poower in that range and the big drop in power is the 8 degrees being pulled for 6500rpms . Try calling the tuner and ask what was done

Aslo remember that having the SS box in place pulls 1 1/2 degree's from signal delay

Last edited by booger; Feb 27, 2006 at 04:03 PM.

Feb 27, 2006 | 04:34 PM

#10

Rizlam

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From: UK

OK, I'll try and get a dump of the map. But are you saying that the net effect of getting that hike at 5K means that I'll automatically lose power at 6K? Sorry, bit confused.

Feb 27, 2006 | 05:02 PM

#11

booger

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From: council bluffs Ia.

do you have the R4 program on a laptop ? And the connections to hook up to the SS box? If you do...and know how to do it . You can dowload the maps from the box. Or you can ask the tuner for a copy of your r4 file

Feb 27, 2006 | 05:21 PM

#12

Rizlam

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From: UK

Yep, have the R4 software, they wouldn't be able to tune the thing otherwise! I'll ask them to email me the backed up map and look at the numbers in my R4 software. What would I be looking for?

Also, any other ideas for why there might be this big nosedive at 6000 rpm?

Mar 1, 2006 | 02:57 AM

#13

Rizlam

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From: UK

Maps

OK guys, here's the pertinent bit of my map. Any clues?

Code:

FUELLING																
rpm	0 PSI	0.5 PSI	1 PSI	1.5 PSI	2 PSI	2.5 PSI	3 PSI	3.5 PSI	4 PSI	4.5 PSI	5 PSI	5.5 PSI	6 PSI	6.5 PSI	7 PSI	7.5 PSI
500	10	10	10	10	10	10	10	10	10	10	10	10	10	10	10	10
1000	10	10	10	10	10	10	10	10	10	10	10	10	10	10	10	10
1500	10	10	10	10	10	10	10	10	10	10	10	10	10	10	10	10
2000	10	10	10	10	10	10	10	10	10	10	10	10	10	10	10	10
2500	10	10.3	10.3	10.3	10.3	10.3	10.3	10.3	10.3	10.3	10.3	10.3	10.3	10.3	10.3	10.3
3000	10	10.5	10.1	10.1	10.1	10.1	10.1	10.1	10.1	10.1	10.1	10.1	10.1	10.1	10.1	10.1
3500	10	10.8	10.4	10.4	10.4	10.4	10.4	10.4	10.4	10.4	10.4	10.4	10.4	10.4	10.4	10.4
4000	10	10.5	10.5	10.5	10.5	10.2	10.2	10.2	10.2	10.5	10.5	10.5	10.5	10.5	10.5	10.5
4500	10	10.1	10.1	10.1	10.1	9.9	9.9	9.9	9.9	10.1	10.1	10.1	10.1	10.1	10.1	10.1
5000	10	9.5	9.5	9.5	9.5	9.5	9.5	9.5	9.5	9.5	9.5	9.5	9.5	9.5	9.5	9.5
5500	10	9.5	9.5	9.5	9.5	9.5	9.5	9.5	9.5	9.5	9.3	8.9	8.9	8.9	8.9	8.9
6000	10	9.3	9.3	9.3	9.3	9.3	9.3	9.3	9.3	9.3	9.1	8.5	8.5	8.5	8.5	8.5
6500	10	9.3	9.3	9.3	9.3	9.3	9.3	9.3	9.3	9.3	9.1	8.6	8.6	8.6	8.6	8.6
7000	10	9.3	9.3	9.3	9.3	9.3	9.3	9.3	9.3	9.3	9.3	9.3	9.3	9.3	9.3	9.3
7500	10	9.8	9.8	9.8	9.8	9.8	9.8	9.8	9.8	9.8	9.8	9.8	9.8	9.8	9.8	9.8
8000	10	9.8	9.8	9.8	9.8	9.8	9.8	9.8	9.8	9.8	9.8	9.8	9.8	9.8	9.8	9.8

IGNITION RETARD																
rpm	0 PSI	0.5 PSI	1 PSI	1.5 PSI	2 PSI	2.5 PSI	3 PSI	3.5 PSI	4 PSI	4.5 PSI	5 PSI	5.5 PSI	6 PSI	6.5 PSI	7 PSI	7.5 PSI
500	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
1000	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
1500	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
2000	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
2500	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
3000	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
3500	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
4000	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
4500	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
5000	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1
5500	2	2	2	2	2	2	2	2	2	2	2	2	2	2	2	2
6000	3	3	3	3	3	3	3	3	3	3	3	3	3	3	4	4
6500	9	9	9	9	9	9	9	9	9	9	9	9	9	9	9	9
7000	11	11	11	11	11	11	11	11	11	11	11	11	11	11	11	11
7500	15	15	15	15	15	15	15	15	15	15	15	15	15	15	15	15
8000	15	15	15	15	15	15	15	15	15	15	15	15	15	15	15	15

Mar 1, 2006 | 04:45 AM

#14

jpc350z

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From: columbia md.

Couple of observations..1. Your A/F seems a tad rich and appears to be the stock S.S map.. Mine and others I have seen have been tuned to around 11 accross the board..2. Timing retard above 5k seems to have no logic particularly 6.5 to 7.0k.. As Booger pointed out the S.S. timing is gradual..Might wanna go with S.S. stock timing and see results...

Mar 1, 2006 | 04:49 AM

#15

booger

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From: council bluffs Ia.

Yup ..just like I said . They took out less timing at 6000rpm and more at 6500rpm . Plus the fact your A/F goes from 11.5 [ good ] to 10.5 [ rich ] in the same rpm range

Mar 1, 2006 | 04:56 AM

#16

Rizlam

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I'm a bit confused. The fuelling map above isn't like the stock SS map at all, as far as I can see. What are you saying needs to be done?

Mar 1, 2006 | 04:59 AM

#17

plumpzz

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What clutch are you using? If your using stock clutch, perhaps its slipping? Could u feel the car stutter?

Mar 1, 2006 | 05:09 AM

#18

Rizlam

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From: UK

Stock clutch, but the only slippage I've had has been from stationary or when going WOT at very low revs. At 6000 rpm it's solid. No stutter.

Mar 1, 2006 | 05:17 AM

#19

jpc350z

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From: columbia md.

Quote:

Originally Posted by Rizlam

I'm a bit confused. The fuelling map above isn't like the stock SS map at all, as far as I can see. What are you saying needs to be done?

It appears to be too rich. The stock S.S fuel maps are rich.. Try for 11.5 accross the rpm range..Try search section for Vortech dyno's and I believe you will see for cars that have been dyno tuned there A/F ratio will be around 11.5...