B20 build

[tdz840]

Originally Posted by Amazonjulian

He spent three hours on my car and the labour charge from memory- don't have the invoice in front of me was £150. I really rate him.

Julian
That's good value, I paid around £250 for half that time and just the two runs, initial then validation run.
I'm also interested in how well the 123tune curve is optimised to my engine. I'm tuning using a innovate LS1 but I'm not convinced the results are accurate.
Russ

[Derek UK]

"Derek my understanding is that both toque and HP always cross at 5250rpm. I don't recall the exact reasons but it involves James Watt and his famous equation."

Those numbers don't equate. Power and torque curves can cross anywhere within reason. Watt could hardly envisage an engine turning at that speed let alone have max torque at the same speed. Steam engines have big torque at low revs as do diesels and electric motors but what about an engine that has peak power at 9k, peak torque might be at 8k on that one.

[Amazonjulian]

The actual total was £230 but included in this was £70 worth of bits. Andy is not the greatest fan of 123. I had already got the timing on mine pretty close but mine is not the version where you create your own curves. It does have on it the custom curve from Amazon cars. I'm going to fit a 74 thermostat. Joe who did the head work for me reports getting 5 more horses by running the engine a little cooler on his cortina mk 1 race car. That's not my primary reason for doing it but it's a cheap tweak. I'm also going to fit an oil pressure guage. Having gone this far, it seems a good idea to be able to monitor this crucial variable closely.

[Hat]

Three hours on timing and mixture?

[Saner]

It's the point at which 1hp = 1ft lb. which is 5252rpm according to Watts Equation.

Which is the theory on which all dynometers are derived.

[tdz840]

Originally Posted by Saner

It's the point at which 1hp = 1ft lb. which is 5252rpm according to Watts Equation.

Which is the theory on which all dynometers are derived.

Aaah yes, that reminds me of the first part of a lecture which I then subsequently fell asleep!
However a bit of detective work finds this which builds on your explanation.
Thanks!
Russ

http://trust-me-im-an-engineer.kinja...rpm-1650651680

[Derek UK]

I see where you going there. Yes the divisor is 5250 and that is the cross over point on the curves. The engine will feel best there, but it doesn't mean much as it doesn't denote either peak torque or peak power.

http://auto.howstuffworks.com/horsepower1.htm
http://auto.howstuffworks.com/question622.htm

Interesting stuff.

[Amazonjulian]

So following all the hard work last spring not to mention the help from folk on this forum, we enjoyed the summer in the car until our house move put a stop to fun in August. Running up to this, I had noticed how quickly the car heated up especially in traffic but then we were also having a particularly hot period of weather. So today finally having some time to myself, I got the old girl out of her winter slumber with a particular view to seeing how the heating up issue was. Well the car warmed up quickly and it was noticeable how quickly the guage started to climb once I had stopped. the fuelling is spot on and the timing too. It's under 500 miles since the rolling road tune. I have a seventy something thermostat fitted ( brain ) I have an ally radiator ( thanks Russ) and an electric fan ( eBay) with a 82/87 thermostat plumbed into that. At idle it took two minutes of the fan running to bring the temperature down below 82 giving me a minute and a half before it sparked up again. With an outside temperature of 11 or 12 degrees it doesn't bode too well for the summer months. When on the move the temperature stays steady in the middle but as soon as you are stopped it gallops up. I would be grateful for your thoughts. Mine so far are: not very good electric blower fan, mounted in front of rad? Maybe the head gasket needs another tighten? Not so efficient water pump- transferred from my old engine.

[Derek UK]

It's quite normal for the temperature gauge to go up after you stop. That's just due to heat soak at the back of the head, and the gauge, being mechanical, shows that happening. If it was an electric gauge that switched off with the ignition you wouldn't notice that. From your post it reads as if the electric fan is working properly. Having an adjustable fan control is useful, as you can give it a tweak to have it switch on a few degrees earlier if you want to. Having a manual override to on switch inside always good but if the set point is good you'll rarely need it.
If the fan circuit doesn't go off with the ignition switch the fan will sometimes come on as you're walking away from the car and that can be disconcerting, and initially you may be tempted to stay until it switches off in case it just carries on running and flattens the battery. Some turbo cars have a fan to cool the turbo after you switch off and usually work on a timer. You can make it as complicated as you like.

[Ron Kwas]

Aj;

A rise in indicated Temp after stopping with Motor (more specifically, coolant circulation) shut off, is typical and not unusual as Derek notes...some increase in Temp when moving very slowly and in hot conditions is also typical, but going into the Red (er... White, for a 122!) means that Radiator is not shedding heat adequately ...and lowering the Tstat Temp rating is just not going to help, when Rad is at its limits! That when guys start thinking about installing an Electric Cooling Fan to help move air through the Rad and help it shed heat, or even modifying the Coolant Distribution Pipe in the Cyl Head.

It should be noted that circulation and Rad effectiveness should be checked and assured before even considering such major changes! Check Temp delta from Rad-in (Top) to Rad-out (Bottom)...it should be significant!...if not, anything which might impede circulation (internal sclerosis or other blockage of the Rad) should be eliminated.

Cheers