MaxLugo

Say both cars (ie 1.8t 4x4 and NA Civic) and ticking over. If you tap the civic's throttle pedal, you see the revs rise up pretty quiclky. Now you try that in the 1.8t (DBW) and you barely get any response. I know the turbocharger is creating lot's of backpressure, but how slow is too slow when it comes to throttle response in our cars?

Last time i vagcom'd my car, i had the multiplicative trim in -20%, which indicates something is wrong, but i havent found out what it is. Anyway, is my richness choking the engine at low revs and reducing my throttle response, or are the 1.8t really that lifeless?

Sheaf

Smaller capacity revvy NA cars will always have quicker throttle response than FI larger capacity cars.

There's more momentum in the engine to gain/loose, I expect VAG 1.8t has a much larger flywheel, and of course, at idle it doesn't have any boost, making it effectively a very low compression ratio NA engine compared to a high compression ratio engine.

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Parents: '02 Octavia 1.9TDi
Me: '99 V Honda Accord Type-R

MaxLugo

Actually, my comparison car was a Nissan Primera 2.0 AT, so it was bigger than the 1.8. But the point you make of the low compression at idle makes lots of sense.

Now, could my -20% multi trim be reducing my response even further?

SkodiRS

Also have to consider the DBW has a built in "sneeze factor" so you will loose a certain amount of immediate response.

I expect the cable throttle 1.8t to have slightly better response to accelerator inputs.

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Adrian.

DGW

Which measuring block is that trim reading in?

PS: Just found it on Ross-Tech's website here. It's Group 032 - and a figure somewhere near +/- 10% is normal.

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Denis

2002 Octavia 1.8T 4X4 turbo Estate - rebreathed on by Jabba ... 31.93mpg
2007 Fabia vRS - CC, ESP and full leather trim by Seat Surgeons ...48.09 mpg...

TKW

That's what I wanted to write, but didn't know how to phrase it ... the electronics have a little dampening effect. Look at it as a low-pass filter if you like, although I quite like the concept of a sneeze factor

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Octavia 4x4

MaxLugo

true, dbw does have the filter, but what i'm refering to as "tap" is to fully step on the throttle and release right away. Fully opening the intake and letting go. At idle, i dont get more than 400 instantaneous revs from doing this. Would i be right by assuming that the same thing happens to evo's and wrx's and pretty much every turbocharged car?

Now that we are already talking about all this stuff, what can be causing the -20% multi trim, besides the fpr ?

MC Bodge

re-mapped and fitted with a K&N throttle repsonse is improved, but nowhere near that of my old, slightly tweaked Focus.

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Mk1 Octavia vRS. The thinking man's Hot Hatch.
PS. Give Cyclists Room! We're quite vulnerable. If I can slap your window, you're too close

Goochie

I think its a turbo thing. The 350Z revs much more freely than a remapped 1.8T and the Z has a much large capacity engine too.

Nigel26

its not to do with the flywheel in the 1.8t is it? i'm sure i read somewhere that they have a single mass flywheel to keep the idle steady when rolling in traffic...

may be barking up the wrong tree there.

i've noticed the throttle response on mine is nothing like the R19 16v i had before. i just put it down to DBW and being turbo'd.

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Sea Grey Mondeo Titanium X

SkodiRS

Should be duel mass flywheel....it's a fair point.

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Adrian.

Nigel26

sorry, yes dual mass... not single...

its something else i notice with the vRS, how slow the revs die off when your blip the throttle... i know thats down to the flywheel. maybe the same is said for the revs rising...

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Sea Grey Mondeo Titanium X

MaxLugo

How many of you revmatch all the time? I always do, on everyday driving because i hate the shock of the clutch having to match engine speed with transmission speed. The slow throttle response makes revmatching hard to do propperly, specially because of how long it takes to rev the engine. How do you cope with this, or am i the only freak who doesnt like to use the synchros a lot?

SkodiRS

I could understand how remapping may improve response but not a filter......a freer flowing filter will only allow more, cooler air to enter which will produce more power.

However from a standing start you are not inputting cooler air...more ambient temp air or even hot air from heat soak.

On the move the response it deffo better but then that's due to freer flowing cooler air.

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Adrian.

MC Bodge

Having done both at the same time, I can't be totally sure which made the difference can I?

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Mk1 Octavia vRS. The thinking man's Hot Hatch.
PS. Give Cyclists Room! We're quite vulnerable. If I can slap your window, you're too close