B - Class FWD

[BarbecuePete]

It was the lack of torque that I suffered with on the Familia, as I was after torque in these cars it kinda fell at the first hurdle.. lol

Saying that though you may have gone for the best build by going for the cams on the Familia, I found this site the other day....

http://www.epi-eng.com/piston_engine_technology/power_and_torque.htm

Its got a lot of info on how RPM, Torque and Power are related with a couple really good graphs... Also check out the link to the BMEP values... Im tempted to do some experiments when I get back online, I think it could be that magic number that Hop was looking for to explain how different engines compare to one another...

From reading the info there and what I remember when I built one up the Familia has a very flat torque curve so you need to go for the cams to get the most out of the engine by moving the peak torque higher in the rev range as it doesn't produce much torque low down, it also supports what you said about keeping the revs high... think F1 engine in miniture.. lol  Saying that.. it would probably also benifit more from the block upgrade so it runs better at high revs..

[Spiny Anteater]

If I remember correctly, the figures for my build are about 251bhp and 174 lb-ft. The torque curve doesn't feel very flat to me - the feel from the car is of a very peaky engine typical of many Japanese motors. However, I need to go back and check first before I say it's definitely not flat. It may even be a twin-cam engine, and I'll see if that's right from the torque/power curves too, but it doesn't feel as obviously twin-cammy as the Hondas in game, or indeed my road car.

The main thinking behind going for the cams is the reason why that is my first go-to addition to a build - by making the car breathe better you reduce the torque losses at high revs, and this in turn leads to better horsepower over a wider rev range. As this also leads to an increased red line (in most cases), I feel that you can make more use of this extra horsepower than the relatively low torque figure might suggest.

[BarbecuePete]

You're right about getting more from the engine at high revs than the torque figure would suggest...

Taking the F1 engine as an example again (this is from the link) it only produces a peak torque of 214 lb-ft and at peak power it only produces 206 lb-ft... but because its producing this torque at 19,000rpm it means you get 755bhp... To get that much power from a 'normal' engine at say 8,00rpm you'd need the engine to be producing almost 490 lb-ft, so as you say low torque doesn't matter if you can get the engine to spin quickly enough...

I think the torque curve was fairly flat on the Familia, or at least it wasn't a V-TEC type cam anyway. I was avoiding those because I knew they don't produce much torque and the Familia stood out because I was expecting it to have a V-TEC like nearly all the other Aisan cars I looked at.. I could be wrong though, I think I may have already gone slightly delirious due to having to go Cold Turkey from Forza 

[Spiny Anteater]

Turns out I was a bit out with my figures - the figures for my car are 255bhp and 194 lb-ft. Red line is at 7800rpm and having looked at the power and torque curves it's definitely not twin cam. 

You're also not wrong about the torque curve looking flat, or at least it does at first glance. One of my gripes about is the state of the graphs. We're all familiar with the ridiculous scaling on the gear chart, but I also don't like the scaling on the engine charts either. This car is a case in point - the graph is scaled up to allow the maiximum engine output on the chart which is all well and good, but what happens when you have a lightly modified engine like this one? It becomes difficult to see the characteristics of a curve when, like this torque curve, it only takes up a third of the chart.

In actual fact the torque curve is not particularly flat and does rise up to about 6000rpm or so (didn't check the exact figures), but that's not immediately obvious from a quick glance at the chart due to the flattening effect of it being squashed into the bottom of the graph.

[BarbecuePete]

Yeah the Scaling on the graphs in FM2 is kinda usless really, considering this is meant to be a sim racer there should really be better information available to tune aspects of the car such as the gearing..

I'd also really like a feature that was available in Need for Speed Underground 2... You could actually dyno tune the ECU mapping (and turbo if you had one fitted) to make the engine better for the type of racing you were doing.. wouldn't it be cool to be able to fit better parts to an engine and then re-map the ECU to bring the PI back down..   

[bimmerlovere39]

I miss that feature...

it was win

 

[Spiny Anteater]

Got to run the Familia a bit more last night, and I think I may have found it's niche. Having turned the aero down to minimum, it has a great top speed and handles pretty well, but the acceleration sucks. It seems it may be pretty good on flowing tracks, and even better on tracks like Sunset or the 'Ring with long straights.

Speaking of turning the aero down, I tried that on my Focus ST which had maximum aero and was brilliant through the corners, but got toasted on the straights. The result of that was that it still lost out a bit on long straights, but it still handles well in the corners, and pulls strongly in the lower gears. This is a serious "go to" car for the snakes and similar tracks Now all I need is to make a few additions to the orangeness...

[sk15kev]

Pete, Did you ever get around to that Sentra?  Was planning to do one myself after getting skinne dby one last week.

[BarbecuePete]

I do have the Sentra built up but I've just not had chance to run it through all the tracks yet because of doing other things, but I'll try and get it up soon...

[sk15kev]

If you can post it up, I will build put it in one of my battles.