Rolling Road Results

OK - Tin helmet and flak jacket on now - and about to be late for my flight:

Is the air flow that is plotted on the x-axis not the corrected airflow? i.e. corrected back to make sure that the readings are what would have been achived if the air going into the turbine was at standard air temp and pressure and hence does that not lead to the conclusion that, if you have to correct the airflow for differences in intake air temperature that it does impact on the mass of air that the turbine will flow?

I think there are two temperature factors here that are getting mixed up - there's the intake temperature of the air which I agree should not change as a result of the test, but which could give different end results to the test if the intake temp is different from test to test and hence the results need to be corrected in order to ensure that different tests are comparable

And then there's the temperature change the occurs in the gas as a result of it being pressurised (your Delta T). That is a factor of pressure and not flow I agree. And for the purposes of that change measurement, the intake air temp can be assumed as arbitrary.

What I understand, is that the air flow T (say its 20 degrees for instance) is pretty irrellevant as depending on the PR ratio, it will go up or down etc...The air flow T just has to be an arbitary figure just to have some kind of reference, but your right, it is a standard inlet temp into the compressor...

but...

The islands in the centre of the map show efficiency, with the left over turning to heat, so 75 efficient, 25% heat and more so as it goes to the next lower efficiency island...

..and , then we have efficiency of the intercooler etc, so all these variables make the difference between inlet temp and engine temp (as these comp maps don't have to be automotive based) vary widely.

Most of these maps use lb/min as it takes into account an air density level rather than CFM which varies alot with heat..

This is a good program to play with to watch all the variables..

http://not2fast.wryday.com/turbo/glossa ... tyCycle=80

Ah, I think I see what your getting at - if the T is a lower temp then you should in theory make more power, flow more etc...

Yes, but with cars and intercooling as we know, we could have a car with high inlet temps and good intercooling and another with low inlet temps and no intercooling and get the same or lower power...

If all things being equal then yes...

I'd be up for putting my car on the rollers next year, as they are close to home too, but my car is no longer "std", mainly the 10inch Carhege Cooler and increased boost, both of which can easily be turned off or down to simulate a std car.

movin on from grass cutting then

I think I'll go down the pub for a quiet drink, I just hope that there is no quiz or debate being thrashed out over the bar tonight.

I don't care - I've got 300 ft/lbs per ton and its very fast!!

I don't care - I've got 300 ft/lbs per ton and its very fast!!

A610 lump 250 horse standard...... now 297....... all that hassle and cash..... Whatever

Considering the whole project has still cost less than 1 CAR member paid to have a standard A610 engine removed rebuilt and refitted at a French specialist I think thats pretty reasonable. I suppose all your mods on your cars come free? How much does it cost to build a 9 sec RX7 drag car? It has been a shit load of hassle though!

I don't care - I've got 300 ft/lbs per ton and its very fast!!

Exactly, it doesnt matter. As I always like to say, Id rather have a fast car that has moderate power, than get beaten by somebody and know I had all the power in the world..

What you have to realise is you engine has the potential to make loads of power if you want to go to the next step so the figure you have at the moment is not the b-all and end all (' thats the saying, not sure how you write it )

Dont spend money on fiddling....go and shed some weight off it for easy real life power gains. Have you ever weighed your car?....aircon, (boy is the aircon pump a hefty beast!) big stereosystem, charge cooler, 17" wheels all round......I'd be suprised if it is much less than 1300kgs. I have stripped mine to the bone (other than glass,CC and Azevs) and its sitting at 1040-1050 now.......think about the potential power to weight advantage loosing even 100kgs would make!
To get 250bhp per ton you need 325bhp (assuming 1300 is right!).....I only need 260bhp (currently I dont even have 1 hamster so Ive got a long way to go!!! ).
Cheapest way to go faster known to man!

I'm off to Stansted to see what they make of your engine analyser at the x-ray machine. Should be fun

DG - you'll be pleased to know that your diagnosic pod contains no trace of any explosive materials. Strangely though - it was not the pod and associated wiring that drew me to their attention but the windscreen wiper arms that were in my computer bag. The girl on the x-ray machine could not figure out what the strange shape was and called a bloke over who was similarly baffled. So a bag search and swab for explosives ensued. Oh how we laughed when a pair of odd wiper arms was produced from a laptop bag. Anyhow - off to plug it in and see what planet my car thinks it running on.

I don't really want to start stripping the car to be honest - I've got another one for that! The plan was always to try and create a nice driveable street car I'd really like to get it running better in every day driving situations. That has been the downer for me with the ECU, I'm sure it is capable of running the car more smoothly in normal driving but until I get my lambda working I can't use the adaptive mapping. I've learnt the software well enough to map the car on the road myself now I think so won't be needing anymore rolling road visits. Does anyone ever use the full potential of an aftermarket ECU, they all have lots of fantastic functions but to set it all up is so time consuming I'm sure nobody bothers. Car makers spends millions developing ECU's then test them for 100's of thousands of miles in all extremes of climate - if it only took a few hours on RR road they would be rubbish! I think the thing to do is get your head around the software then constantly toy with it over many months and it should gradually improve.

I know what you mean about the extra functions.....I'm using precisely none.....its all time and money!

[phildini]

Bloody hell these many posts in such little time..... It's like being back in my maths class.... Anyway well done Tony

A610 lump 250 horse standard...... now 297....... all that hassle and cash..... Whatever

Considering the whole project has still cost less than 1 CAR member paid to have a standard A610 engine removed rebuilt and refitted at a French specialist I think thats pretty reasonable. I suppose all your mods on your cars come free? How much does it cost to build a 9 sec RX7 drag car? It has been a shit load of hassle though!

RX7 dragster...... cost me....... nothing !

so called "Renault specialists" see you coming........ and rip you off just like a dealer
it don't take that long to drop an engine out of one.....

spider mods just cost me the parts......easy to fit! and its reliable i don't see my engine melting down tomorrow

cool power and torque for only 15 psi boost and limited set up time mate . It will be very fast i'm sure and i'll dought very much if any other gta's will keep up as they normally go like an old donkey !!!!!!!!