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another dyno curve
https://www.ausmini.com/forums/viewtopic.php?f=5&t=44887		 Page 1 of 2
Author:  simon k [ Fri Aug 15, 2008 10:28 pm ]
Post subject:  another dyno curve
on the subject of dyno curves, we put my cooper on the chassis dyno yesterday as part of sorting out the right needles for it....

the wiggly line is a bit of a giggle.

Image

Twin 1.5"s, the current needles are CP4, I've plotted some other needles, and I think I'm going to get FG's, along with some new jets, shafts and bushes

Image

With the CP4's, the mixture goes too rich with the throttle wide open, and is very lean at cruise - no matter what RPM it is doing. At wide open, the needles are open to station 8, and the AFR is around 11, and at cruise, they're just past station 3, and the AFR is around 16. I like the look of FG because it's thinner in the middle, and a bit fatter at the tip, but not too fat

I'm actually a bit confused to why they only open to station 8 at WOT - I don't know what the dashpot springs are, I think I picked the weakest out of the 2 pairs I have

It also seems I have a backpressure problem, we haven't tested it yet, but all signs point to it (also fitted a posivac that isn't giving the response we expect)
Author:  drmini in aust [ Fri Aug 15, 2008 10:59 pm ]
Post subject: 
Simon,
CP4s were apparently stock in the Police pack twin HS4s but Karcraft suggested #6, so that's what I run in Barney's 1293 now.
Angelo ran those too at MRC dyno day (the first one) and it drew a straight line at 13.0:1.
Plot those on yer chart... :wink:
Author:  kiwiinwgtn [ Tue Aug 19, 2008 6:20 pm ]
Post subject: 
Hi doing the same thing fitting twin 1.5s, what cam are you running

Ta

kiwiinwgtn
Author:  simon k [ Tue Aug 19, 2008 9:23 pm ]
Post subject: 
the cam is an RE13

otherwise, it's 1330, pulsar dizzy, hypatec pistons, slightly lightened flywheel with my stock Cooper S head on it

I've made a web page that searches and charts SU needles, showing the #6 against CP6 backs up what Kev said, and I've found with my car on the dyno. I want richer at station 3, and leaner at station 8 - #6 needle gives this. The FG that I liked might still be OK, but I'd need to have the adjuster nuts all the way up, I'll try #6 first

have a look:

http://www.morrismini.com/SUNeedlesV2.aspx?linklist=6;CP4;FG;
Author:  minidrifter [ Wed Aug 20, 2008 12:09 am ]
Post subject:  Re: another dyno curve
simon k wrote:
the wiggly line is a bit of a giggle.


you think yours is a bit of a giggle :shock: :lol:

your web page is great btw :wink:
Author:  smiling_simon [ Thu Aug 21, 2008 1:49 pm ]
Post subject:  Re: another dyno curve
simon k wrote:
on the subject of dyno curves, we put my cooper on the chassis dyno yesterday as part of sorting out the right needles for it....

the wiggly line is a bit of a giggle.


May just be me but why do people make dyno plots with kmph on the (x) axis? Surely RPM is more meaningful?

It will tell you more about the camshaft and breathing/overlap. Also plotting torque on the (y) along with AFR and hp (least important).

I managed 84 bhp @ wheels with a similar setup to yours - electric dissy / hypatecs (1330) / lightened flywheel but with a weber.

You could probably get a few more hp out of that engine. Has the pulsar dissy advance been checked / modified for a 1275 mini(by Graham Russell perhaps)? What tappet settings you running?
Author:  simon k [ Thu Aug 21, 2008 3:01 pm ]
Post subject:  Re: another dyno curve
smiling_simon wrote:
simon k wrote:
on the subject of dyno curves, we put my cooper on the chassis dyno yesterday as part of sorting out the right needles for it....

the wiggly line is a bit of a giggle.


May just be me but why do people make dyno plots with kmph on the (x) axis? Surely RPM is more meaningful?

It will tell you more about the camshaft and breathing/overlap. Also plotting torque on the (y) along with AFR and hp (least important).

I managed 84 bhp @ wheels with a similar setup to yours - electric dissy / hypatecs (1330) / lightened flywheel but with a weber.

You could probably get a few more hp out of that engine. Has the pulsar dissy advance been checked / modified for a 1275 mini(by Graham Russell perhaps)? What tappet settings you running?


I've always said the same thing.... in this case, the tacho input to the dyno was wildly innacurate, the bloke who runs the workshop twiddled some knobs, but it wasn't working so we ditched it - we only did those power runs after some more formal & accurate checking of the mixture at each RPM band.

I limited the advance in the dizzy, but it still has the full compliment of nissan springs in it, Kev said to take 1 or 2 out - not sure exactly what GR does on top of that(?). Tho another step in my tuning plan is that once we have a better mixture, to map the optimal advance for each RPM band, and sort the dizzy to suit, or I'll make a programmable one (jaycar kit or megajolt)

84 @ wheels from a 1330 is very impressive - I'd be keen to see a 1/4 mile time, as it ought to be mid 14's judging by other cars at the sydney events. In Vizard's big yellow book, he gives a formula to work out bhp given the cars weight and speed when it reaches the white line
Author:  doogie [ Fri Aug 22, 2008 9:56 am ]
Post subject:  Re: another dyno curve
simon k wrote:
on the subject of dyno curves, we put my cooper on the chassis dyno yesterday as part of sorting out the right needles for it....

the wiggly line is a bit of a giggle.

Image

Twin 1.5"s, the current needles are CP4, I've plotted some other needles, and I think I'm going to get FG's, along with some new jets, shafts and bushes

Image

With the CP4's, the mixture goes too rich with the throttle wide open, and is very lean at cruise - no matter what RPM it is doing. At wide open, the needles are open to station 8, and the AFR is around 11, and at cruise, they're just past station 3, and the AFR is around 16. I like the look of FG because it's thinner in the middle, and a bit fatter at the tip, but not too fat

I'm actually a bit confused to why they only open to station 8 at WOT - I don't know what the dashpot springs are, I think I picked the weakest out of the 2 pairs I have

It also seems I have a backpressure problem, we haven't tested it yet, but all signs point to it (also fitted a posivac that isn't giving the response we expect)


Simon, thats a pretty healthy HP figure, around 11 more HP than Scrapper 2 well done. I better go find some grunt, don't want you beating us at Jugiong in January. :wink:

Doogie
Author:  simon k [ Fri Aug 22, 2008 10:50 am ]
Post subject:  Re: another dyno curve
2 S's & a clubman wrote:
Simon, thats a pretty healthy HP figure, around 11 more HP than Scrapper 2 well done. I better go find some grunt, don't want you beating us at Jugiong in January. :wink:

Doogie


you don't have to trust that my dyno is the same, but I'm hoping for another 8 or 10 in the next few months.....
Author:  doogie [ Fri Aug 22, 2008 11:47 am ]
Post subject:  Re: another dyno curve
simon k wrote:
2 S's & a clubman wrote:
Simon, thats a pretty healthy HP figure, around 11 more HP than Scrapper 2 well done. I better go find some grunt, don't want you beating us at Jugiong in January. :wink:

Doogie


you don't have to trust that my dyno is the same, but I'm hoping for another 8 or 10 in the next few months.....


Now thats just showing off mate!!!

Doogie
Author:  smiling_simon [ Fri Aug 22, 2008 12:00 pm ]
Post subject:  Re: another dyno curve
Quote:
I limited the advance in the dizzy, but it still has the full compliment of nissan springs in it, Kev said to take 1 or 2 out - not sure exactly what GR does on top of that(?).


That's probably right... most people aim for 5-10 degrees static, 28 degrees dissy advance which is the cooper s setting. GR also mods the dissy shaft for correct oil feed.

Quote:
Tho another step in my tuning plan is that once we have a better mixture, to map the optimal advance for each RPM band, and sort the dizzy to suit, or I'll make a programmable one (jaycar kit or megajolt).


That would help - I don't really know how much extra % you will get from this, but I am a firm believer you can get more performance if you can test/adjust more factors. Only problem is you may spend alot of time doing this and as soon as you change your fuel/dissy/rockers/carb you will need to retest.

Basic idea with race cars is to pick the rev range you are going to race in, tune it at WOT within that powerband and stuff the rest of the range.

If you want to use a megajolt consider getting a crank sensor/coil pack - it'll be much more accurate!
Author:  simon k [ Fri Aug 22, 2008 1:05 pm ]
Post subject:  Re: another dyno curve
smiling_simon wrote:

That would help - I don't really know how much extra % you will get from this, but I am a firm believer you can get more performance if you can test/adjust more factors. Only problem is you may spend alot of time doing this and as soon as you change your fuel/dissy/rockers/carb you will need to retest.


retesting isn't a problem - my guru and I think the same way, we like to look for those little changes that make the 1 or 2 hp's, so we fiddle around... test, fiddle, test... the only problem is time

smiling_simon wrote:
Basic idea with race cars is to pick the rev range you are going to race in, tune it at WOT within that powerband and stuff the rest of the range.


indeed.... no good for me tho - this is my daily :) (and motorkhanas etc.)

smiling_simon wrote:
If you want to use a megajolt consider getting a crank sensor/coil pack - it'll be much more accurate!


yep - that's the plan, as per Pristic's setup & bin the dizzy altogether
Author:  simon k [ Fri Aug 22, 2008 1:08 pm ]
Post subject:  Re: another dyno curve
2 S's & a clubman wrote:
simon k wrote:
2 S's & a clubman wrote:
Simon, thats a pretty healthy HP figure, around 11 more HP than Scrapper 2 well done. I better go find some grunt, don't want you beating us at Jugiong in January. :wink:

Doogie


you don't have to trust that my dyno is the same, but I'm hoping for another 8 or 10 in the next few months.....


Now thats just showing off mate!!!

Doogie


I've said it before Doogie.... what I lack in ability, I intend to make up for with more grunt, fancy gizmos and whatever cheating I can get away with
Author:  1310/71 [ Fri Aug 22, 2008 2:53 pm ]
Post subject: 
How many minis are coming to Jugiong, God damn it?
At this rate I'll have to dust off a renault and preserve credibility. :D
KB
Author:  JC [ Fri Aug 22, 2008 3:04 pm ]
Post subject: 
Mate I think you need to shut the gate, a few horses have escaped.
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