My rolling road figures from today

[Craig855S]

Engine power figures calculated from wheel figures are utter toss!!! theyre close but just far too generic. The main thing im intrested in is

 

"How much power/torque your drivewheels apply to the roller?" IT is absolutely impossible to get this figure wrong! And before and after RRs should be done to prove mods,i think the next time i go to an RR i may buy my powerchip for the car,ill RR it once,then fit my chip,then RR it again,see if it changes. Best RR i know of is PECOs Research and developement rolling road,its a 1000BHP RR using 1 massive roller under the ground, last time i went it proved my 1.4 PTE as 70BHP at teh wheels calculated (bollox figure but near enough) it also calculated a 2.0 scort at 126BHP-wheels and a civic VTI standard at 161BHP calculated (spot on what it shud be,well 1bhp more) Good results i reckon

[davespages]

I agree on your point of mods and consistancy.

Rolling roads vary on thie calculations to obtain bhp and torque figures.

 

The key with a rolling road is if you do mods, go back to the same set of rollers and get figures showing an increase (or decrease) in bhp/torque for your mods.

Obviously air temp can effect this so timing in the day/year also helps consistancy.

But the biggest variable with rolling roads is thier calculations.

I have put 2.0 TB, powerchip and a pannel filter on my GTi now, just sourcing a 2.0 MAF.

When that is done, i will RE-RUN the gti on the same rolling road (in a morning) so that i get not nesecarilly new accurate figures, but a proven GAIN/LOSS on the old figures.

 

Also, my JUMP powerchip is working fine with a SLUG ecu...

I'll get pete to do an extra run, with and without the chip to see if it is making a difference... placebo effect an all that.

[Craig855S]

do with and without the 2.0 MAF mate as i cant see how they do anything,its not like changing the sensor changes the amount of air it sucks in.the difference for the 2.0 MAF is its voltage range (its min-max airflow is HIGHER than the 1.8 so itll just make it run rich yes) A RR test will prove it if ur up for it mate?

[ScORTED]

scoop you have very strong convictions but you often come out with shite - it is oinly a sensor but a different one with a greater capacity for measuring airflow hence this will give a different signal to the ecu - which in turn controls the the fueling.. so go figure - this isn't a personal attack

[davespages]

Well i have never had any figures to suggest the MAF makes a difference, when i fitted mine i noticed no difference.

 

However my mates now 130 spec GTi had a decat put on which free'd things up, then he got a cat back system fitted which slowed it down and made it hesitant snd sluggish, he even considered putting the standard exhaust back on.

Then when i gave him my 2.0 maf from my old escort, he fitted it... it ran lumpy for a minute or so then settled and it pulls much better now.

There is the chance his 1.8 was is clogged, but then it shouldnt be as he had my 1.8 one when i fitted the 2.0l one about 9 months back.

[Craig855S]

different signal to the ECU,yeah i know,thats what im saying. For x amount of air flow a 1.8 MAF would tell ECU to put amount x of fuel in, where a 2.0 MAF would think "ah thats hardly any air,so lets put in LESS than X amount of fuel"

 

 

ie/1.8 MAF makes 1.8 ecu tell 1.8 injectors to flow at 60% for given air

2.0 MAF makes 2.8 ecu tell 1.8 injectors to flow at 55% for same amount of air,cos 2.0 MAF thinks its speaking to a 2.0 ECU and 2.0 injectors

 

I think that makes sense of it

[Mike C]

[davespages]

2.0 MAF makes 2.8 ecu tell 1.8 injectors to flow at 55%

 

Well it could be like that, but not on a 2.8 ECU

Well the picture is there. anyhow...

 

So how does a 1.6 maf tell a 1.6 ecu to fuel 1.6 injectors in a 1.8?

Only pulling ya leg buddy.

[Craig855S]

i reckon my 1.6 management runs my 1.8 moderately well cos the ECU will be recieving signals from its MAF and thinking,woah,where sucking loads of air so lets flow injectors to match,which will prob be at 100% flow rate,especially when the air is denser in the mornings

[basskiddanny]

I agree on your point of mods and consistancy.

Rolling roads vary on thie calculations to obtain bhp and torque figures.

 

The key with a rolling road is if you do mods, go back to the same set of rollers and get figures showing an increase (or decrease) in bhp/torque for your mods.

Obviously air temp can effect this so timing in the day/year also helps consistancy.

But the biggest variable with rolling roads is thier calculations.

I have put 2.0 TB, powerchip and a pannel filter on my GTi now, just sourcing a 2.0 MAF.

When that is done, i will RE-RUN the gti on the same rolling road (in a morning) so that i get not nesecarilly new accurate figures, but a proven GAIN/LOSS on the old figures.

 

Also, my JUMP powerchip is working fine with a SLUG ecu...

I'll get pete to do an extra run, with and without the chip to see if it is making a difference... placebo effect an all that.

 

Same ECU as my 1.8

 

Not that it makes any difference lol.

[davespages]

Well my Si was JUMP, my mates GTi is JEST and my new GTi is SLUG.

[basskiddanny]

Well my Si was JUMP, my mates GTi is JEST and my new GTi is SLUG.

 

Rob is looking at this now. What is your ECU rob? On your GTi?

 

Also Dave do you know if theres any differences between the ECU's that come with the1.8's?

[Craig855S]

i know the autos deffo have a difference inside the ECU,but i dont think any of the others do. I have a JEST one i cant use with my 1.8 and im currently still on a TUNA 1.6 one

[davespages]

Scoop, if you come across a 1.8 Si in red in a scrap yard with the reg P313 NMB, nab the ECU and i have 2 keys for it still

 

Anyhow...

 

The different ECU code just signified revisions in the ecu program and ignition/fueling maps but seeing as the later 1.8's were 115ps (113.4bhp) then i dont see the problem and my SLUG ecu runs ok with a JUMP powerchip.