rally510,

Ok so your peak torque was at 5000rpm. What was it in Nm ?
Here is my L18 as an example- mild botom end, Datsport head,25/65 cam
79.8 rwhp @ 6011 rpm, with 101.2 ftlbs @ 3703 rpm
or
59.5 rwKw @ 6011 rpm, with 137.3 Nm @ 3703 rpm

I'm with Dave on this one, until you can supply us with more info regarding your setup etc, it will be hard to give any advice.

What sized chokes are you running on those 45's ?
What fuel were you using for the run? PULP/AVGAS/Optimax/C-16 ?? Opps just read you used AVGAS

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1975 P610/180B SSS ex PRC3 Rally car (parts car)
1974 P610/180B SSS (parts car)
1972 P510/1600 Currently sitting untouched
1977 P610/180B Wagon Daily Driver

I'll believe it when I see the dyno sheet, from a dynodynamics dynamometer, in shootout mode, with a shootout stamp. Sorry.

I think there are different types of avgas too. If its only running 10.2:1 compression it doesn't need avgas, nor 107+ octane.

Dave

_________________
USA Daily: 2014 Nissan GT-R, very minor modifications for the track
USA Project: 1978 280Z, minor suspension upgrades, VK56DE conversion in progress. SOLD
AUS Race Car: 1973 240Z, L28ET, Autronic, GT35R. SOLD
AUS Project: 1972 1600, 3200km old S15 SR20DET, ground up rebuild. SOLD

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Classic Auto Fabrications:
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http://www.lescollinsracing.com/

I'm not the trusting type. No offence intended.

Dave

_________________
USA Daily: 2014 Nissan GT-R, very minor modifications for the track
USA Project: 1978 280Z, minor suspension upgrades, VK56DE conversion in progress. SOLD
AUS Race Car: 1973 240Z, L28ET, Autronic, GT35R. SOLD
AUS Project: 1972 1600, 3200km old S15 SR20DET, ground up rebuild. SOLD

I am with Dave here.
The specs you have given simply dont add up.
My L20 runs more compression (10.5:1), a 76 works cam and is extensively modified. It makes 92rwkw on BP Ultimate 98.
Lets see a dyno sheet.
My Dyno sheet is here
http://www.datsun510.com/photopost/show ... =1&cat=500
Jake

turbo510,

How much torque did your car make and at what rpm ?
as it wasnt on you dyno sheet.
I'm sure that beast sounds awesome. Top job. I'm Uber jealous
Any idea what you would have at the flywheel ?

_________________
1975 P610/180B SSS ex PRC3 Rally car (parts car)
1974 P610/180B SSS (parts car)
1972 P510/1600 Currently sitting untouched
1977 P610/180B Wagon Daily Driver

Dave,

The lower line on the graph is tractive effort (N) which CAN be converted to a torque figure directly but is way too difficult. Easier to just convert using the power line

You can convert power to torque using the following formula:

Nm = Kw / RPM * 0.000104727

90Kw at 5400 is 159Nm.

Dave

_________________
USA Daily: 2014 Nissan GT-R, very minor modifications for the track
USA Project: 1978 280Z, minor suspension upgrades, VK56DE conversion in progress. SOLD
AUS Race Car: 1973 240Z, L28ET, Autronic, GT35R. SOLD
AUS Project: 1972 1600, 3200km old S15 SR20DET, ground up rebuild. SOLD

Oh that makes more sense. Thanx.

Seems his peak was in around 4500rpm with a drop off at 5500rpm.
odd how the torque curve has 3 distinct "lumps" at 3500,4500,5500.

Mine went up like a rocket then dropped like a stone, due to the Jacto me thinks. I will have to dig up that bloody sheet.

I would like to see a NA HP section, where members can posted their Dyno sheets and motor info. Like we currently have for the 1/4mile and circuit times. But make it "no dyno sheet, no posting".

_________________
1975 P610/180B SSS ex PRC3 Rally car (parts car)
1974 P610/180B SSS (parts car)
1972 P510/1600 Currently sitting untouched
1977 P610/180B Wagon Daily Driver

We tried a power figure thread for people to post. Noone could agree on what was required and I cracked it and removed it. You guys work out exactly what you want and I'll happily add it.

Dave

_________________
USA Daily: 2014 Nissan GT-R, very minor modifications for the track
USA Project: 1978 280Z, minor suspension upgrades, VK56DE conversion in progress. SOLD
AUS Race Car: 1973 240Z, L28ET, Autronic, GT35R. SOLD
AUS Project: 1972 1600, 3200km old S15 SR20DET, ground up rebuild. SOLD

hang on - he hasn't given any specs! Someone here guesstimated a compression ratio, and that's about all you've got to go by...

rally510 doesn't seem to know exactly what's done to it. It sounds to me like this was the engine that was in the car when he bought it. It is possible to get that power from 10.2 CR, but it would have to be a very well built engine - if its not an optomistic dyno readout, there really isn't much more to be squeezed out of a 2000cc 2v engine. Will be interesting to see what that cam was...

at the end of the day dyno sheets don't prove anything anyway, unless you go to a club dyno day to compare cars on the same dyno under the same testing parameters. I've seen variances of up to 30% between different dynos.

I'm not going to say anymore, this discussion is why I cracked it last time.

Dave

_________________
USA Daily: 2014 Nissan GT-R, very minor modifications for the track
USA Project: 1978 280Z, minor suspension upgrades, VK56DE conversion in progress. SOLD
AUS Race Car: 1973 240Z, L28ET, Autronic, GT35R. SOLD
AUS Project: 1972 1600, 3200km old S15 SR20DET, ground up rebuild. SOLD

I would have to agree with you on the Dyno variances.
This I would put down to old/worn not serviced Dynos giving higher readings.
I have seen the same car at one Dyno tuner one week make 230 rwkw, then the next week on another dyno make 25 rwkw less power, Similair weather conditions.
Same car went on "brand spanking new" Dyno shortly after and made 205 rwkw again.
Was obvious that the first Dyno was giving higher figures.

_________________
1975 P610/180B SSS ex PRC3 Rally car (parts car)
1974 P610/180B SSS (parts car)
1972 P510/1600 Currently sitting untouched
1977 P610/180B Wagon Daily Driver

I know all dyno's read different.
The dyno my car was done on was calibrated the week before my car went on. Comparing my car to other similiar L20's that have been tuned on the same dyno the figures are consistent.
Any Melbourne guys who know Errol Torber and Errol Smith who tuned it would know their reputation for understating power figures. They tune racecars for track performance not dyno queens for car shows.

DatSSS73,
I would say the lumps in the torque graph are due to Webers. A good efi setup should smooth the whole graph out but the twin 45's will do for now. Will save the EFI for the forced induction.

On that note I am out of this discussion. I am just sick of hearing about huge power outputs without anything to back them up. Everyone knows dyno's differ in power readings and a lot of tuners use correction factors to make the end power output look better to justify the high prices they charge.
Jake

where do you race? Any pics of the car??

so are you saying that you think 92kW at the wheels is as good as L series get? Or is there another reason you automatically disbelieve anyone who claims more bhp than you?

200bhp at the flywheel (~150bhp/~110kW at the wheels) isn't out of the question, but definitely requires a good engine builder who's familiar with the L series engines. You won't get much more out of a 2000cc L series, which is why i said if its got 143bhp at the wheels, don't muck with it!

Whoops. Didnt mean to open such a can of worms here!
This was never intended as hp bragging. At the end of the day a horsepower figure means nothing to me, it is the horsepower gain that is important when you go on a dyno. This car went on the dyno to make sure it was making as much power as possible. It is a dedicated rally car after all.
As stated, i do not know the spec of this motor. This is the first time i have had it apart since i have owned the car.
It has always been a competitive car with many class wins and a regional title since i have had it. Pehaps now i know why!
To me, the figure seems about right. This motor revs like lightning and pulls well past 8 grand. But, I know full well the problems with dyno variances and the crooks (not all, but definately the one in my area) that run them.
I had hoped to find out the camshaft spec today but didnt hear back so hopefully tomorrow.
The torque figue on the dyno sheet is 637ft/lb but i think you have to account for diff ratio? I'm sure someone will have the formula.
Maybe its just the way that kiwis build their engines that produces more power? Look at the stone brothers for example...

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