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Model specific boards => Golf mk5 => Topic started by: Peskarik on 15 October 2008, 18:25

Title: Higher outside temp = slower acceleration?
Post by: Peskarik on 15 October 2008, 18:25
Today was 19C degrees outside when I was going home. It's highway, 70-100 mph.
The car feels slower to accelerate than when the outside temperature is say 14 degrees.  :undecided:
I have the map, but stock internals.
I know there was a post discussing the temperature issue.

I guess the problem is intake air being too hot, right?
Do you think Carbonio intake or bigger IC would alleviate the problem? :undecided:
Title: Re: Higher outside temp = slower acceleration?
Post by: SteveS on 15 October 2008, 18:28
cooler air combusts more, providing more power. so if the temp is hotter of the air, less combustion!
Title: Re: Higher outside temp = slower acceleration?
Post by: RedRobin on 15 October 2008, 18:29
....

It's well known on turbo'd cars. S3 intercooler or Forge Twintercooler (or both!) is the favourite cure. Carbonio won't help much I don't think - It's just a more efficient air intake rather than a low mounted 'cold' air intake.
Title: Re: Higher outside temp = slower acceleration?
Post by: Hurdy on 15 October 2008, 19:05
cooler air combusts more, providing more power. so if the temp is hotter of the air, less combustion!

Not quite. :smiley:

Cooler air is denser and contains more oxygen when compared like for like with a same volume of warmer air. Ergo more oxygen in the same volume is drawn into the intake giving a small increase in power. Similarly, when it is colder the intercooler is able to keep the system cooler and therefore more efficient and so has less power loss. The two combined give a decent increase in useable power in colder weather. :smiley:
Title: Re: Higher outside temp = slower acceleration?
Post by: R32UK on 15 October 2008, 19:12
Today was 19C degrees outside when I was going home. It's highway, 70-100 mph.
The car feels slower to accelerate than when the outside temperature is say 14 degrees.  :undecided:
I have the map, but stock internals.
I know there was a post discussing the temperature issue.

I guess the problem is intake air being too hot, right?
Do you think Carbonio intake or bigger IC would alleviate the problem? :undecided:

i think someone is possibly trying to justify a new mod???    :lipsrsealed: :rolleyes:
Title: Re: Higher outside temp = slower acceleration?
Post by: Hurdy on 15 October 2008, 19:14
I think you maybe right there  :rolleyes:
Title: Re: Higher outside temp = slower acceleration?
Post by: RedRobin on 15 October 2008, 19:22
I think you maybe right there  :rolleyes:

....Well if anyone knows the tell-tale signs, you do! :evil:
Title: Re: Higher outside temp = slower acceleration?
Post by: SteveS on 15 October 2008, 19:28
so yea... basically wot i said... :-|
Title: Re: Higher outside temp = slower acceleration?
Post by: Hurdy on 15 October 2008, 19:33
so yea... basically wot i said... :-|

Sorry....went into T_T pedant mode their for a second :embarassed: :laugh:
Title: Re: Higher outside temp = slower acceleration?
Post by: topher on 15 October 2008, 19:33
You're talking ambient temps here, so intake temps. Intercoolers won't do squat against that, you need a decent cold air intake. If you're thinking of the type of system that uses a cone filter somewhere in the wing or behind the bumper vents, make sure you get a 'sock' for the filter or you risk sucking in water. Hydraulic lock is very messy!
Title: Re: Higher outside temp = slower acceleration?
Post by: RedRobin on 15 October 2008, 19:43
You're talking ambient temps here, so intake temps. Intercoolers won't do squat against that, you need a decent cold air intake. If you're thinking of the type of system that uses a cone filter somewhere in the wing or behind the bumper vents, make sure you get a 'sock' for the filter or you risk sucking in water. Hydraulic lock is very messy!

....I don't know enough to challenge that, but others have often said that an aftermarket intercooler helps. It's why Forge sell more Twintercoolers in hotter climates IIRC.

Of course, open fog grilles are the best solution  :wink: :evil: :evil: :evil: :evil:
Title: Re: Higher outside temp = slower acceleration?
Post by: topher on 15 October 2008, 20:06
More efficient intercoolers certainly help in warmer climates (well, they help in general really), where the air passing over the fins of the core is cooling the charge temps i.e after it's already gone through the turbo, but in this instance we're dealing with intake temps where the only thing the air is passing through is an air filter and the air-mass meter before it hits the turbo.
Obviously the very best solution would be to use both :tongue: but when you compare just how hot charge temps are compared to intake anyway, this little problem of feeling slower on warm days can be solved by getting the denser air into the system in the first place... because once its in there it's going to hit 40 degrees anyway.
Title: Re: Higher outside temp = slower acceleration?
Post by: E30M3 on 15 October 2008, 20:11
What kind of Sock for the CAI ? ? a normal smelly one ?  :grin:

seriosuly what kind of sock, can you buy it from the manufacturer of the air intake ?
Title: Re: Higher outside temp = slower acceleration?
Post by: topher on 15 October 2008, 20:13
Usually yeah, i know K&N do one, in various colours!
Title: Re: Higher outside temp = slower acceleration?
Post by: E30M3 on 15 October 2008, 20:15
does the sock affect performance somewhat ? ?

does Forge do one for there CAI, or is it just a K&N stuck onto their pipeS ?

thanks for the help.
Title: Re: Higher outside temp = slower acceleration?
Post by: RedRobin on 15 October 2008, 20:16
More efficient intercoolers certainly help in warmer climates (well, they help in general really), where the air passing over the fins of the core is cooling the charge temps i.e after it's already gone through the turbo, but in this instance we're dealing with intake temps where the only thing the air is passing through is an air filter and the air-mass meter before it hits the turbo.
Obviously the very best solution would be to use both :tongue: but when you compare just how hot charge temps are compared to intake anyway, this little problem of feeling slower on warm days can be solved by getting the denser air into the system in the first place... because once its in there it's going to hit 40 degrees anyway.

.... :cool: Thanks for the useful explanation :afro:

[You are appreciated even if some of us sometimes rant at you!]
Title: Re: Higher outside temp = slower acceleration?
Post by: topher on 15 October 2008, 20:20
here's an example of one http://www.force-metric.com/proddetail.asp?prod=5017r

they're specifically for dry filters (if you're using an oiled filter, shame on you!)

i'm sure the manufacturers will claim they don't affect performance, but they must do slighty.. not something i'd be too concerned about with a forced induction engine though.. it won't be a restriction to worry about.
Title: Re: Higher outside temp = slower acceleration?
Post by: E30M3 on 15 October 2008, 20:23
thank you Topher, was wondering why Forge state their CAi should not be used in the rain !

I'll enquire with Forge whether they make one for their system .
Title: Re: Higher outside temp = slower acceleration?
Post by: RedRobin on 15 October 2008, 20:25
....

Some of the Mk4 R32 guys I know have used a different anti-hydro system which is installed in the pipe run.
Title: Re: Higher outside temp = slower acceleration?
Post by: topher on 15 October 2008, 20:30
Yep there are ways to catch it in the pipe run too, but in my personal opinion it makes more sense to leave the vortex of air well alone to do its thing once it's moving. Probably less of a concern with N/A engines though.
Title: Re: Higher outside temp = slower acceleration?
Post by: E30M3 on 15 October 2008, 20:30
....

Some of the Mk4 R32 guys I know have used a different anti-hydro system which is installed in the pipe run.

Robin how does that method work/look ? any ideas ?

All you lot with you constant modding has me in fits before i go bed  :laugh:

thoughts of intercoolers , CAI, Divertor valves keeping going round my head !!   :sick:  :grin:

Title: Re: Higher outside temp = slower acceleration?
Post by: RedRobin on 15 October 2008, 20:51
....

Some of the Mk4 R32 guys I know have used a different anti-hydro system which is installed in the pipe run.

Robin how does that method work/look ? any ideas ?

All you lot with you constant modding has me in fits before i go bed  :laugh:

thoughts of intercoolers , CAI, Divertor valves keeping going round my head !!   :sick:  :grin:


....Sorry but I'm not into telling men weird bedtime stories!

On the other hand, if you are female and post a pic, I'll quickly reconsider! :evil:

I'd have to consult my Biali Motorsport buddies - A couple of them did it. But what topher posted about air vortices being more critical on a turbo'd engine seems a more important consideration.
Title: Re: Higher outside temp = slower acceleration?
Post by: Peskarik on 15 October 2008, 23:05
Today was 19C degrees outside when I was going home. It's highway, 70-100 mph.
The car feels slower to accelerate than when the outside temperature is say 14 degrees.  :undecided:
I have the map, but stock internals.
I know there was a post discussing the temperature issue.

I guess the problem is intake air being too hot, right?
Do you think Carbonio intake or bigger IC would alleviate the problem? :undecided:

i think someone is possibly trying to justify a new mod???    :lipsrsealed: :rolleyes:

Oettinger Stage 2. could be.
but looking at what is going on in the world, I wonder if I should save some money for bread and milk  :lipsrsealed:
Title: Re: Higher outside temp = slower acceleration?
Post by: Peskarik on 15 October 2008, 23:09
You're talking ambient temps here, so intake temps. Intercoolers won't do squat against that, you need a decent cold air intake. If you're thinking of the type of system that uses a cone filter somewhere in the wing or behind the bumper vents, make sure you get a 'sock' for the filter or you risk sucking in water. Hydraulic lock is very messy!

there is no chance I take the cover off the engine.
Carbonio would be maximum I'd go for.
But if neither IC nor Carbonio offer much help for the problem at hand (which is - feeling of slower acceleration when ambient temp is high) then I see no point in installing them. Now it is Autumn, I wonder what the car will feel like in Summer, when it is not 19 but 29 degrees outside. I also wonder if the map is more of a problem (in terms of reduced engine/turbine lifespan) than fun-factor at those Summer temps.  :undecided:
Title: Re: Higher outside temp = slower acceleration?
Post by: topher on 15 October 2008, 23:19
The carbonio kit will help, but unless you control the weather or can manipulate natural physics you'll never completely overcome the issue that some days you'll be sucking in warmer, less oxygen rich air :smiley:
Title: Re: Higher outside temp = slower acceleration?
Post by: RedRobin on 15 October 2008, 23:30
....

It's also why rolling-road results can be a bit meaningless - A turbo'd car will perform slightly differently on every day of the year. I've driven mine in Summer in Italy and up mountains etc and any difference in performance is only slight and you get used to it and drive accordingly anyway - It's no big deal unless your are on the race track!
Title: Re: Higher outside temp = slower acceleration?
Post by: Peskarik on 16 October 2008, 19:27
....

It's also why rolling-road results can be a bit meaningless - A turbo'd car will perform slightly differently on every day of the year. I've driven mine in Summer in Italy and up mountains etc and any difference in performance is only slight and you get used to it and drive accordingly anyway - It's no big deal unless your are on the race track!

I don't know, RR, you car is mechanically modded, mine is only remapped. And the difference is very noticeable - the car is less "crisp" when it is warm outside, even the engine sound changes. A bit of loss of performance is ok (though I am addicted to the acceleration now  :embarassed:), but I wonder if higher temp means trouble for the engine.