Just been browsing another forum and there's a lad banging on about how powerful his car is....

Now, it could just be me, but do these graphs look a bit, er, odd?





Bearing in mind this is a normally aspirated 2.0 Redtop Vauxhaull engine...

Torque seems more like a turbo diesel

 

That figure on the graph is incorrect for the torque, its not even vaguely what the line on the graph shows!

 

My sentiments exactly Chip.

Yet he's got 4 pages of people on this other forum who are all very impressed with his rocket ship corsa

 

nah that looks perfectly normal to me, specially where the power drops off just after 190 and then shoot back up again, happens all the time, and the lovely flat torque curve is nice aswell,

when my car was on a rolling road i got this shit graph where things started low and then went up with the revs before peaking and then going lower

 

Apologies for the size of the image, but this is what I would expect to see from a 230bph or so XE

 

If its even a vaguely half decent build of car, it should keep with a stage 3 escos round a track, so IS a rocket ship to most folk I would imagine mate.

Just that torque figure thats a nonsense though.

 

So, the Blue plot is BHP and if so, it looks to me as though the graph had an odd spike at the end, which they have disregarded, rightly so.

But if that is the case, where did they get 280odd lb/ft from?? It's actually 180odd if you disregard that shitty bit at the end after 5500?

Either way, looks tosh to me.

 

Fully agreed mate, revvy N/A wide powerband in something that weighs as much as your foreskin IS quick

But the way they're going on about it you'd think someone had stuck Rods engine into a kitcar

 

Photoshop spings to mind LOL

 

PMSL

All relative I guess, was having this discussion with a mate of mine last night, depending on what else ive been driving, my 3door can feel either really quick or really slow, coming from my audi tdi, its ballistic, but when I was driving it after twitchells stripped out mk2 astra with about 400bhp, it felt like a pedal car.

I guess for a lot of the kids you are chatting to, that corsa is the fastest car they have EVER been in and hence mentally quick to them, where as obviously to you its just "ok" as you drive FAR quicker cars on a regular basis through work etc

 

Don't you have to type in the figures to print on that type of RR?

Operator has just hit 2 instead of 1 - 186 lb/ft is about right

 

That would be a very simple explanation!

 

Agreed.

One question though, if its a highly tuned engine, wheres the rest of the rev range? I'll be honest and say I dont know a huge amount about the engine in question, but 6000rpm? My diesel runabout will rev to that

 

Standard one will pull cleanly well past 6K mate.

They do peak relatively early though on standard cams.


Will, what is the spec of the engine itself?

 

Look at the graph, i think its a miss print and should be 186.98 lb/ft [not 286.98]. I just about touches this and at no point is it anywhere near 286lb/ft. Still seems a little high to me but then o dont know these engines at all.

Edit: way to slow lol

 

A basic spec, like standard engine + TB's will give around 165lbft typically.
Slightly hotter spec, like one would have for 225bhp, will typically give about 180lbft
A full blown 10,000 pounds and more race motor with about 270bhp, will give about the torque on this graph, lol (ie around mid to high 180s)

 

Cheers Chip.

 

So if thats the case, and hes making 190 engine bhp, is the whole graph horseshit?

 

TBH mate, what that graph looks like to me, is that they synch'ed the RPM wrongly.

This will have 2 effects:
BHP curve = unaffected in height, will shift down the RPM
Torque curve = will get taller and shift down the RPM
Rev range = will shift down the RPM


Given the way that the rev counters over read on a lot of vauxhalls, I suspect thats what the issue is with both the torque and rpm range.

 

That makes sense

 

Well, other than me saying it had 2 effects, and then listing 3, LOL

 

Do the lines cross in the right place?

 

I wasn't gonna pick you up on that, but I did have a chuckle to myself lol

 

The BHP and torque scales are different.

 

At 5252 its about 175 ish on both, so yes they "cross"

 

I knew there were certain graphs where on first glance they didn't meet, and wasn't sure on this one!

Cheers guys