dyno

Dave · Post by **Dave** » Fri Mar 24, 2006 10:29 am

Leigh,

You are running way rich. There's more power to be had for sure! As a ballpark for a N/A, carbed motor, you want to shoot for 12.5:1. That 17.5:1 that shows up in the stats on the dyno sheet but not on the graph itself is BS. Probably when you let up off the throttle after the pull was over and the graphing was no longer going. Pay no attention to that number. Like Alvin said, talk to the carb tuning gurus on this site. I can't begin to tell you WHAT you need to do to achieve it, but I can tell you there's more power to be had down low and in the midrange if you lean it out a bit. Below 4,000 you're down around 12:1 and below. That's turbo motor territory! No need for you to ever be down there. Above 4,500 things start looking good.

Get that guy leaned out down low and see if you can eek out another degree or two of advanced timing before it starts to ping. I'll bet ya got another 10 Hp hiding in there.

Just as a side note, you are PERFECTLY safe if you decide to do nothing. You can run around all day long with A/F ratios like that and not worry. I don't want to give you the impression that you need additional tuning because your current set-up is unsafe for the engine. It's only warranted if you want to squeeze every last drop of power out. So, if you decide not to change anything, cool. Just go enjoy the car as is!

Daryl Smith · Post by **Daryl Smith** » Sat Mar 25, 2006 9:42 pm

mikew wrote:
""With only 1000km on it, this engine turned 85kw (115hp) at the wheels, at 5700rpm. That's with 34mm chokes in the webers, which I think may be limiting ultimate horsepower, so I am trying to find some 36mm chokes for it. With the current setup though the low-mid rpm torque is amazing. ""

This is with 40mm carbs with 34mm chokes on a H20 based engine.

The reason I am posting it here is I WANT TO KNOW if anyone has tried putting the 40mm carbs on a U20?

It doesn't seem to be any worse for horsepower, and would quite likely improve low and midrange torque, methinks.....???

mikew, any idea how much power you might gain by going to the 36mm chokes?

'course you all know I am going with EFI, I am just a very curious kinda guy, and if I had the $$$$ I would try it!

Unfortunately I am cash strapped so I have to put ideas up for other people to thimk about, and try... or shoot me down and point out the errors of my ways.

OK, I am going back out to the garage now.....

(Almost ready to fire up "Frankie" again. Keep yer fingers crossed...)

Daryl Smith · Post by **Daryl Smith** » Sun Mar 26, 2006 1:17 pm

Here is a site with some interesting Nissan/Datsun dyno results:

http://www.datsuns.com/Tech/datsundyno.htm

Down near the bottom they list an SR20DE with a ROADSTER 5 spd!?!?

mikew · Post by **mikew** » Mon Mar 27, 2006 1:00 am

I don't know until I try it, but if the 34's are indeed a limiting factor, we should be able to squeeze a few more hp out of it.

As I mentioned in another thread the other day, I've learned that the 36mm chokes don't work very well in the DCOE40's - 34mm is the practical limit, so.... especially considering I'm fed up with constantly fiddling with the Webers, I'm thinking I'll swap them for the 44mm Mikuni's I have sitting in a box - they have 37mm chokes in them.

Another guy over here with a VERY similar engine to mine, but running the Mikuni's is getting around 95kw (130hp) at the wheels.

mike

Dave · Post by **Dave** » Mon Mar 27, 2006 8:52 am

Down near the bottom they list an SR20DE with a ROADSTER 5 spd!?!?

If you look directly below that entry, there's one for a KA24 powered 510 with a 5 speed. The 510, of course, never came with a 5 speed. So, I think it's just poorly worded and not intended to convey that the roadster is using the stock 5 speed and the 510 is using a stock (because there's no such thing) 5 speed.

nomadtrash · Post by **nomadtrash** » Wed Mar 29, 2006 1:44 pm

Did you notice the KA24DE with basic bolt-on's put out 169/170. Not bad considering that none of the other 4 bangers were even close.

Dave · Post by **Dave** » Wed Mar 29, 2006 7:02 pm

nomadtrash wrote:Did you notice the KA24DE with basic bolt-on's put out 169/170. Not bad considering that none of the other 4 bangers were even close.

You know what they say..."No replacement for displacement..."

Import_sounds-of-mid-GA · Wed Mar 29, 2006 7:14 pm

Dave wrote:You know what they say..."No replacement for displacement..."

*cough*nitrous*cough*

DELETED · Post by **DELETED** » Wed Mar 29, 2006 9:18 pm

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Daryl Smith · Post by **Daryl Smith** » Fri Mar 31, 2006 2:51 am

"SR20DE (Datsun Roadster 5-speed)
Stock except for necessary changes to make fit into Datsun Roadster
130.8hp @ 6500rpm
117.5ft/lbs @ 4800rpm"

Of course your right! For some reason I thought it was in a 510.

The KA may not rev like the SR but they can make REALLY good power in the revs they use. Part of the reason, along with parts and availability, that I would put a KA into the roadster before an SR.......

When I was at Z-Therapy a few years ago they had a Turbo KA in a 510 that they said was making over 400 hp at the wheels.

DELETED · Post by **DELETED** » Fri Mar 31, 2006 12:17 pm

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Conner · Post by **Conner** » Fri Mar 31, 2006 12:28 pm

Turbonetics has just released a new turbo kit for the QR25DE found in the Sentra SE-Rs: 250 HP at the wheels @ 8psi on an unmodified QR. The upper limits of boost have not yet been tested, but are probably similar to the KA.