hesitation when trying to blip

R

road warrior

Senior member
 Burton On trent
the car runs beautifully, never misses, even tickover = all lovely - except when i try to blip the throttle from say 3rd to 2nd between the gears it wont anymore, not in sport or normal - its just stopped - any thoughts ?
 
Well we can probably say it's down to an issue with air, fuel or ignition...

Air:
Do you have an air leak?
Is your air filter blocked?
Is an inlet hose collapsing under the vacuum induced by a large throttle opening?

Fuel:
Is your fuel pressure suffering as a result of a tired fuel pump?
Is fuel pressure low because of a blocked fuel filter/fuel pump strainer?
Is one or more injector blocked?

Ignition:
Tired/fouled plugs?
Tired coil/coils?


I currently feel like gambling on fuel. Has your consumption reduced lately? Do you get this same hesitation if you boot it when in gear (particularly at lower revs)?
 
Have you checked the plugs and the points?

Dampness in the distributor cap?

Dodgy HT lead?

:rofl: :rofl: :rofl:
 
As I say, I have No problems aside from being blipless, all else is fine, no missing on acceleration, is there any connection between a gutted back box and the blip, let's face it there is no shortage of gurgling...
 
road warrior said:
As I say, I have No problems aside from being blipless, all else is fine, no missing on acceleration, is there any connection between a gutted back box and the blip, let's face it there is no shortage of gurgling...
Click to expand...

Did the issue start at the same time the backbox was changed? When I was a lad my cars always performed worse when the exhaust rusted off :?
Rob
 
I am aware I have a powerloss since the dlv back box but I don't mind too much, the noise is worth the slight drop so that's fine, but it might affect something like the blip with all the gurgling and noises going on.. If an engine is a musical instrument, then....
 
Smartbear said:
road warrior said:
As I say, I have No problems aside from being blipless, all else is fine, no missing on acceleration, is there any connection between a gutted back box and the blip, let's face it there is no shortage of gurgling...
Click to expand...

Did the issue start at the same time the backbox was changed? When I was a lad my cars always performed worse when the exhaust rusted off :?
Rob
Click to expand...
I think we are thinking along the same lines :thumbsup:
 
wonkydonkey said:
It could well be running lean when you blip then, if you've de-restricted the exhaust. Backward tuning :rofl:
Click to expand...
probably, a likely effect when you fit any aftermarket exhaust.
 
I remember when I fitted a 4 branch exhaust manifold on my 4ltr v8 Lexus, far from increased power I lost power and fuel economy. A bitter disappointment and very expensive.
 
wonkydonkey said:
It could well be running lean when you blip then, if you've de-restricted the exhaust. Backward tuning :rofl:
Click to expand...
I'm still very happy with trade off. The noise is glorious and in real terms I'm more than happy
 
You want to stop trying to blip inbetween gear changes. Think of the stress your putting on your aged ankles! YOU WILL END UP WITH RICKETTS!!! And have to walk round with a purple dot on your forehead to warn people to stay away in case they catch it. :o
 
road warrior said:
wonkydonkey said:
It could well be running lean when you blip then, if you've de-restricted the exhaust. Backward tuning :rofl:
Click to expand...
I'm still very happy with trade off. The noise is glorious and in real terms I'm more than happy
Click to expand...
Motorbikes very often suffer from this same issue. With such short exhaust runs (and being naturally aspirated) they are highly sensitive to any changes to backpressure. Swap exhausts for a better noise and you'll almost always need to give the fuel map a tweak to resolve resultant flat spots.

If this blipping issue bugs you in time (it would for me I think), you could probably take it to someone to map out the problem :)
 
road warrior said:
I am aware I have a powerloss since the dlv back box but I don't mind too much, the noise is worth the slight drop so that's fine, but it might affect something like the blip with all the gurgling and noises going on.. If an engine is a musical instrument, then....
Click to expand...
Has anyone else noticed a drop in power with a fettled backbox or an aftermarket one? I've seen some chatter about this being a potential issue with a backbox delete but nothing about it also being an issue with modded backboxes or aftermarket ones etc
I really don't see how straight piping the backbox with the same diameter pipe as the rest of the exhaust would reduce gas velocity and consequentially effect scavenging etc. If anything the design of the standard backbox with its lack of any real internal piping would act as a restriction, reduce gas velocity and scavenging. Its not like folks are suddenly sticking a 4" full system on, so gas velocity is reduced
 
MACK said:
road warrior said:
I am aware I have a powerloss since the dlv back box but I don't mind too much, the noise is worth the slight drop so that's fine, but it might affect something like the blip with all the gurgling and noises going on.. If an engine is a musical instrument, then....
Click to expand...
Has anyone else noticed a drop in power with a fettled backbox or an aftermarket one? I've seen some chatter about this being a potential issue with a backbox delete but nothing about it also being an issue with modded backboxes or aftermarket ones etc
Click to expand...

I have a DLV modded backbox on my pre-FL 2.5. It was on the car when I got it, so I have nothing to compare it to, but I've always felt that it performs very well and has never felt like it might be lacking. For the OP 'blipping' has never been an issue, so can't shed any light on this.
 
MACK said:
road warrior said:
I am aware I have a powerloss since the dlv back box but I don't mind too much, the noise is worth the slight drop so that's fine, but it might affect something like the blip with all the gurgling and noises going on.. If an engine is a musical instrument, then....
Click to expand...
Has anyone else noticed a drop in power with a fettled backbox or an aftermarket one? I've seen some chatter about this being a potential issue with a backbox delete but nothing about it also being an issue with modded backboxes or aftermarket ones etc
I really don't see how straight piping the backbox with the same diameter pipe as the rest of the exhaust would reduce gas velocity and consequentially effect scavenging etc. If anything the design of the standard backbox with its lack of any real internal piping would act as a restriction, reduce gas velocity and scavenging. Its not like folks are suddenly sticking a 4" full system on, so gas velocity is reduced
Click to expand...

It’s probably going to reduce back pressure with a straight piped rear box which will have an effect on torque, there was a link on here a while back from M3 cutters where someone had dyno tested there car & found it 20-30bhp down with a modded back box :?
Rob
 
Smartbear said:
MACK said:
road warrior said:
I am aware I have a powerloss since the dlv back box but I don't mind too much, the noise is worth the slight drop so that's fine, but it might affect something like the blip with all the gurgling and noises going on.. If an engine is a musical instrument, then....
Click to expand...



Has anyone else noticed a drop in power with a fettled backbox or an aftermarket one? I've seen some chatter about this being a potential issue with a backbox delete but nothing about it also being an issue with modded backboxes or aftermarket ones etc
I really don't see how straight piping the backbox with the same diameter pipe as the rest of the exhaust would reduce gas velocity and consequentially effect scavenging etc. If anything the design of the standard backbox with its lack of any real internal piping would act as a restriction, reduce gas velocity and scavenging. Its not like folks are suddenly sticking a 4" full system on, so gas velocity is reduced
Click to expand...

It’s probably going to reduce back pressure with a straight piped rear box which will have an effect on torque, there was a link on here a while back from M3 cutters where someone had dyno tested there car & found it 20-30bhp down with a modded back box :?
Rob
Click to expand...

guess i will stick with the cd playing loud exhaust noises then :wink:
 
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