My mates LET Corsa went on a set of rollers today. I deffo think there was something fishy going on!

The car at the moment only revs to 7500rpm. But his power figure was 257bhp at 8450rpm. He said to me he thought he didn't rev the car past 5k. I looked at his graph and the bhp and torque lines don't even cross. So deffo under 5252rpm.

Also does it matter what gear the car is run up in? His was run up in 5th, all others in 4th?

I'll name and shame them in a bit!

 

let is the serial number for the 2 litre turbo engine isnt it correct me if im wrong, it will be C20LET for a calibra turbo lump

then the N/A lump will be C20XE if you wondered

 

Yeah sorry Rudey! Its an old Vaux 2.0 16v Turbo.

You can break the code down, it does have a meaning!

C = Catilyser
20 = Engine size
L = Compression (relates to a number think LET's are 9:1, but the L stands for 9:1 - 9.5:1)
E = European market (I think)
T = Turbocharger

New Vaux 2.0 16v Turbos are Z20LET

A Lotus Carlton is a C36GET. It is lower compression than a LET, and a 3.6

Like Pete says the best N/A 2.0 is the C20XE, but newer ones are a C20NE, not as good (Ecotech)

 

The Engine Speed figure depends on what they used to set the RPM of the Rollers against. Has the car got an accurate Tacho?

The peak RPM figure of 8450 is VERY concerning, but a discrepancy there explains why the graph isnt as expected.

The mention of 5k, where did that come from? Are you saying that he thinks that the car didn't exceed 5k on that run? That's unlikely. A run would normally only end if.....

1. The Rev Limit is reached
2. The car stops making power
4. The operator aborts the run (if he hears Det or if the car is unstable on the rollers etc)
3. It self-destructs

However, the lines crossing depends TOTALLY on the configuration of the Graph. They will only cross if the Axis' are equal.

Post the graph so we can make some sense of it.

 

i thought all runs should be in forth for a 1:1 comparison, im no tuner, its the bloke above that can answer everything

 

LOL.

4th is the ideal gear, but 5th isn't too sad. Its just down to knowing how to read the graph.

The only legit reason to run it in 5th is for traction (i.e. if there was a lack of it in 4th).

 

Here is the graph.....

Deffp seems fishy!

 

Look at the oil temp

 

I'd not noticed that one!

 

242nm of torque? thought newton meters was far far less than lb/ft?

 

That's about 178lbs-ft Steve....

 

Oh ok, thats not too sad, but still less than id expect a 250bhp C20LET to give out tho

 

You already did

Their name is on the top of the printout !

 

falkland

 

as above

 

Thats the whole point! It should easily be on par with mine, if not be more!

We worked out from the speed the max power was at he deffo didn;t rev it over 5k in 5th. About 4900 I think. Why would his machine be saying 8800rpm?

 

Shit I forgot about the Name on the sheet

This wasn't my car BTW

 

DOH !

 

falkland performance

 

I was expecting this to be a thread about that bloke in neighbours

 

 

Dodgy rolling road toady...

just noticed that mate..pmsl

 

Falkland

 

Feck

I didn't notice the typo either!

 

rofl

 

To add to that - if you get a power at the wheels figure, the same car run in 3rd rather than 4th will show more. ( and the opposite - same car in 5th will show less ATW than in 4th)

 

That true?? so that in turn would give a lower than ACTUAL "flywheel" figure too yeah??

 

No, that calculates out right, using the actual speed of the wheels I think.

What got me looking at it was an RST got ran up the same day as me - him in 4th, got something like 200 ATW say. Ran mine up in 5th, and I had around the same at 210ish ( ) On the way home though, I'm pissing all over his lighter car on the motorway - go figure.

 

Looks like they mixed up the RPM set point - nothing too major but should have sorted it. The oil temp just looks like ambient so not connected. Your a hard crowd today LOL

 

It's obviously low geared, as 173km/h = 107.497 mph .

 

hello there, the above graph is of my turbo corsa, i asked timrud to post it for me see if anyone could make any sense out of it.

the car was tested in 5th gear and i was informed that they always test them in the gear below the top gear.

now, me and tim worked out that the 257 was made at a little under 4900rpm. on the graph, in my eyes, the power was still building and the boost was still tailing off evenly like its supposed to.

the reason why i have doubts is another corsa turbo there at the same day made 265bhp and 340+ nm of tourque. that car was peaked at 0.8bar of boost, whereas from the above graph mine peaked at 1.3.

the rolling road opperator said my loss of tourque was due to the fact that the engine runs low compression pistons. the pistons are je 87mil instead of the std 86mil. as far as im aware they only lower the compression from 9:1 to 8.5:1 which isnt reall a great lot.

also told me id loose tourque due to the drag of the 6 speed box. the other corsa ran an f20 5 speed which has the same ratio's as the f28 6speed, so i can understand why mine wasnt tested the same in 4th????

when i was sat in the car on the run for the graph above, the clocks in he car didnt show 5000rpm, whereas the other corsa went to over 6700rpm.

maybe i shouldnt worry too much and look at it that my car makes 257bhp below 5000rpm and probably would have made a lot more as it started to spin out the rollers when they had another few goes. the rpm figure on the graph above is wrong. totally wrong. i think he gave up on the run as the red light on the cumputer started flashing like mad as it was reading nearly 9000rpm.

sorry for the long, long, first ever post ive made.

 

Welcome along Mr Muppetsport

 

another CS member

Dont have an answer for you muppet, but how long and professional does your first post look, if only the same could be said about your input on CS

 

10 times a normal CS post

 

yes jr, i am actually quite sensible, i just have a bit of a laugh on that site as there pretty much isnt any technical type people who would be able to give me a good answer to anything. so i search for answers elswhere.

 

Some funny reasons for stuff there - but still looks like they fluffed a run - tried again, wheelspin wheelspin wheelspin, excuse excuse excuse. Nothing too crazy - see it all the time LOL

Do you know a black corsa turbo from glasgow - all kitted up quad front lights etc. See it all time - just wondered if it was any good?

Cheers

Martin

 

hello, sorry no ive no idea about that corsa. im not actually from scotland, im from cumbra, just went up for a rolling road day with corsa sport.

 

i know, only joking