Thank's Munyard,

Would you call the head a downdraft style? It sounds like you have them sussed out!! Is the cam a custom grind? I've never seen one produce power that far up in the rev range!! sorry to be such a nag, but as a L series fan, this thing looks like a ripper.

Do you run the car as PRC or Classic Rally car?

Your right about dyno's, who do you beleive?? I'd love to see what RallyP510's 1600 does down the quarter mile?? I've read about a Yellow 2.4 1600 that does 13.5 from Qld, and there used to be a L20 powered 1600 down here that did 12's with a shot of N02!

Good luck and I hope you give us a full report after the Alpine this weekend! Hopefully you will make Portman wish he was back in a 1600!!

_________________
go the rat

They still have some dish to them don't they - I just ordered 11:1 comp ratio forged pistons from SWR on their reccomendations for a hot n/a street fj. Maybe they aren't totally "flat top" but they up the compression.
I'm also interested in what the change really is - it made a huge difference to how it feels driving it, way more power low down in the rev range.
I got some adjustable gears so i will dial the cams in properly first - but a dyno sheet is definitly on the cards in the future.

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You've gotta love the sound of a n/a Fj at redline...

bluerat
the ports are not really raised much (it looks normal from the outside) as it doesnt really help.
i will agree that about every other head wants downdrafted ports but believe it or not the problem (eventually) with the L-series heads is that the two valves miss the centre of the bore by 4mm (toward the spark plug side) and with the std 12deg valve angles it gets even worse with more valve lift.
basically big valves become shrouded and hit the bore and you have to move them.
the cam is only about 74deg but has about 16mm of valve lift, but i am begining to learn that the cam timing and the extractor design (and good airflow) are what dominate how high they rev.
its a prc legal P3 rally car.
he is rallying tomorow at the natcap (in canberra) its a big state round and he is a fool for running cos it so hard on the car and its the Alpine in a weeks time that really matters.
the alpine will be huge as there are 110 cars and they are all 2wd, no turbos and nearly 1000 total kilometers and datsuns a plenty....

Thanks again Munyard, that very interesting!!! I'm using a 76, but it only makes power to 6400, then drops off quickly, I haven't had it back on the dyno yet, but I suspect it's advanced a tooth to far, I'm keen to try it now. So whats the hot ticket with extractors?? 4 into 1 as per Bob Waar's book? like everything I suspect it's dictated by engine spec's etc

Sorry, I thought the Alpine was the week after Rally Melbourne, but alas it's next weekend, Did they send them over the Mineshaft in the Natcap??

With the new PRC rules are you tempted to build a L20 now or are you happy with the L18? Have you taken the L18 out to 89mm?

Catch you,

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go the rat

N/A FJ's have valve reliefs in them but turbo FJ's do not. And with flat tops I think u might find the deck height of the piston is a smite lower to compensate for the dish in a stocko piston, unless u specify otherwise maybe when ordering your flattops to increase your compression, which u don't really want to do with with a boosted motor but is a good idea if u are running N/A.

Feel free to correct me if I'm wrong anybody

_________________
Vaughan
'70 P130 Super 6
Fiesta XR4 (modified)
Formally: 510 L22B twin webber terror
510 FJ20et (510 FJ)

1973 Datsun 180b sss

L18 bored out 2mm
87mm flat top pistons
smoothed con rods
smoothed crankshaft counter weights
lightened flywheel
modified sump
nismo head gasket
turbo oil pump
Datsport adjustable cam gear and timing chain set
Lightly ported and shaved head
standed size valves
Datsport cam unknown specs
toyota 20valve throttle bodies
malpassi fuel pressure reg
microtech mt4 ecu
vl turbo fuel pump
swr surge tank
locked s2 bluebird dizzy?
extractors 4into2 into1
exedy semi sprung button clutch
standed 180b sss 5speed
180b sedan diff (unknown ratio)
caltex 98ron


Best of 122.9 rwhp on dyno dynamics dyno in shootout mode

Well one atmosphere wasn't enough, so wacked a t28 on it

http://www.farqueue.com.au/manuals/Dyno%20Results/

135rwkw (182 rwhp) @ 8.3 psi


low to mid range was heaps better on the first couple of runs at over 9 psi
but the s13 det injectors were maxed at 90% duty cycle, so need some s15 injectors.
Also going to buy a better boost controller so that we can make maximum boost earlier and hold it.

476Nm of torque is going to be fun

My Latest results.

FJ20ET

_________________
1970 Datsun 1600 FJ20ET
www.qpdc.info

Crikey.
What injectors, turbo and all that stuff are you running Gun?

_________________
1972 Datsun 1600, S14 SR20DET Engineered (204rwkW @ 17psi.)
viewtopic.php?t=6579
#SR20Datsun @SR20Datsun

1600, L20B, 40mm Dellortos, 98 BP, Yokohama 195/50/15, BOC 3.9 diff, Street Torque Dyno Dynamics
My results from dyno night in Alice Springs 24.5.08. Datto 102.5 hp, GT-R 382 hp

http://youtube.com/watch?v=Dt-dzyusz6M

http://youtube.com/watch?v=OLUvFFIFqDg

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Northside Commodore Dismantlers VT - VY
CE Lancer

[ err sorry to be a stick in the mud but its not 476Nm - thats a false reading

here some math as to why not:
to only make the 135.8kW as shown you would need to make that torque at 2033rpm then have it decay away hugely ie:
3000rpm 322.6Nm
4000rpm 241.9Nm
5000rpm 193.5Nm
6000rpm 161.3Nm
7000rpm 138.2Nm
so thats not right,
then we look at it the other way..............blah blah a few calcs later etc tec


looks like the torque has not been corrected for your diff gears. we all know the magic number is 5252rpm and that is where you 126kw of the graph correlated with the (3.76*) 473Nm as per 5252/5252=1

(PEAK TORQUE however) so basically off your 3.76diff ratio
Torque = 476N.M @ 96kmh so then 476/3.76(diff ratio) = 117Nm

curiousdo you have this grap/dyno sheet with road speed anywhere?




PS: this is a gripe at (DYNOS/PRINTOUTS/OPERATORS/SPEED SHOPS) not you mate

_________________
"Stroked is fun, but I'ld rather get blown"
"Redlines are merely suggestions"

my shrinking garage is down to.....
2x 1600s
1x GQ Tray back
1x 300ZX
1x FZR600

yeah I know it doesnt work via the math, I did the same sums and ended up with 2040 rpm as well. My diff ratio is probably helping to distort the figure as well as its a lot lower than 3.7.

but its all comparative.
since the last tune the figure has jumped to 565 Nm so comparatively it now makes another uncorrected 90 Nm at the wheel wheels than it did 2 weeks ago
also makes another 25 rwkw through the lower end.

here's the latest dyno sheet with comparison of the 2 tunes.
http://www.farqueue.com.au/manuals/Dyno ... sr20+t.pdf

I only had race tyres for the car and had a lot of trouble with the softer ones spitting out chunks of rubber, wouldnt show more than 130 rwkw.
I put some mediums on and it jumped 15 kw, they were getting pretty shiny at the end as well , the dyno operator had to let it run up on the rollers.


why the interest in road speed ?

cheers Jeff

ooops my bad. not road speed, engine speed (rpm).

so what is the diff ratio then?

_________________
"Stroked is fun, but I'ld rather get blown"
"Redlines are merely suggestions"

my shrinking garage is down to.....
2x 1600s
1x GQ Tray back
1x 300ZX
1x FZR600

due to some problem with the dyno he couldnt give a graph with the revs, but if you look at the second page it gives revs at speed for one of the runs.

diff is 4.875.

tyres used were 205 x 50 x 15 softs for the first part of the tune
and 205 x 60 x 13 medium softs for the last part of the tune where the readings were taken.

actual torque can be calculated back using the correct roller to wheel size ratio, not sure of the mainline dyno roller size.
it is probably somewhere between 1/2 to 1/3 of the torque figure shown.
so some where between 200 & 300 Nm depending on the actual roller size.
and less at the flywheel due to gearing..........

if your trying to compare torque, motive force should be consistent between different dyno's.

I only recently started getting dyno tunes so have been learning a lot
learning a lot about the tuners as well .........

Another tihng i noticed, when first looking at the dyno sheet was; it says gears: 4 ??
would that have anything to do with the wrong torque reading ?? 4 gears instead or 5 ?
5 gears, you would have a lower final drive ratio ??
or does the gearbox have nothing to do with it ?? ..lol i wouldn't know

burst the bubble there.. but sure 476 nm of torque would be quite fun in a 1600.

Cheers, steve.

_________________
Stephen,
Tanilba Bay Tyres & Mechanical - 4982 3599
Formally "Datsun_16_Hundred".

Thy Beast 1600
Datfusion