Datsun Roadster Forum-311s.org

Finally ready!

richard wrote: Mon Nov 23, 2020 2:41 pm
Finally ready!

Holly Molly
Details Richard , Detail please

Nice!

Anyone got a conversion on the torque to ft/lbs?
Yes, details please!
ITB size?
Header Primary size?

Thanks,

Looks like a excellent build! Quite the header effort too. Should pull really well I’d expect. Nice job Richard!

Daryl Smith wrote: Mon Nov 23, 2020 5:08 pm Anyone got a conversion on the torque to ft/lbs?

Thanks,

232 N/m = 171 lbs/ft

Fun STUFF! I'm waiting to see some specs on the cam. Way cool headers...

JT68 wrote: Mon Nov 23, 2020 8:50 pm Looks like a excellent build! Quite the header effort too. Should pull really well I’d expect. Nice job Richard!

Jim I think I want that next

What is typical/accepted drive train % loss? 10%? 15%? 20%? Trying to get an idea of what it might do on a chassis dyno. See that nice flat air/fuel ratio? That's what I'm looking for! Max torque at 5300rpm, max hp at 7300rpm. I'm thinking the cam has over 300 degrees duration. Cam really comes on after 4500rpm. However, assuming 15% drive-train loss, at 3500 it's making about 9ft-lbs less torque than my engine (116 vs 125ft-lbs. To be accurate, there's a significant dip in torque, so overall it's about equal from 3100rpm to 4800rpm) and at my peak torque at 4800 rpm it's equal (135 vs 134ft-lbs). It's at this point that it really jumps, and 500 rpms later at 5300rpms it's picking up 10ft-lbs more to its peak of 145ft-lbs, while my motor is dropping off to 128ft-lbs. I bet you can feel that! Horse power, which is calculated on torque and rpm, changes accordingly, and the engine keeps pulling and maintaining a high amount of torque while my motor dies off (at 7000rpm I'm at about 95ft-lbs vs his 132ft-lbs... killer). I would love to see specs on that cam, as well as how it was timed! That engine is running really well. This would be a great engine to bolt on different headers since the engine is clearly working very well. Nice job!

" This would be a great engine to bolt on different headers since the engine is clearly working very well. "

Agreed! I would love to see one of these high output U20's with a well built 4-2-1 header.
(Break where 4-1 is supposed to be better than 4-2-1 is ~8,000 rpm)

Got to love tuning with EFI! What was the difference between the first runs with the normal 4-1 type headers and the last with the very long, wrap around the chassis type?

With the power band starting at about 4500, this is clearly setup as a real racing engine and it looks like it will be a good one.

A practical street engine is very different unless you actually plan to stay between 4&8k rpms all the time-which is really not very realistic, smart or practical on the street.

Lots of things would be different most likely starting with the CR, the cam, and the headers.

Looks like it will be a great track engine though, go fast Richard!

I agree JT, but it also doesn't look like a way over-crammed engine with no bottom end (though we have no low rpm data)... it's making good torque at 3000rpms. I drove a buddies car with a big cam that was horrible on the street but a monster above 4500. Stop light to stop light was painful.

I like that this engine is making good power at 3000rpms, and has a very similar torque plot to the Autech with the big bump. Now, if it's unable to start on a hill then it would not be good for me...

Tomc18 wrote: Wed Nov 25, 2020 8:40 pm Got to love tuning with EFI! What was the difference between the first runs with the normal 4-1 type headers and the last with the very long, wrap around the chassis type?

Agreed! I wonder what would happen if we bolted on the typical header we have available? This motor would likely provide some real world info on how much difference it makes and where. Do it Richard! And give us more engine detail!!

Tomc18 wrote: Wed Nov 25, 2020 8:40 pm Got to love tuning with EFI! What was the difference between the first runs with the normal 4-1 type headers and the last with the very long, wrap around the chassis type?

Between 5-7pk more on the whole run,the length is not much more then the first one, we only made diameter bigger after about a third of the length.
The first runs with the normal shape, which is also longer and has some other changes as the standard road headers, but with a smaller diameter stopped at 207pk.