boost lag HELP!!

[Fever]

I recently got my first turbo car - a 2005 6 MPS.
I have noticed that when I let off the accelerator and then press back on all my boost is gone....and takes about 1/2 a second to build back up. Same thing happens between shifts regardless of rpm.

Is this normal for an MPS?

I had the car fully inspected by Tunehouse (pre purchase inspection for $200) - but I'm starting to think they did a shit job, as they missed that the top right engine mount was totally collapsed. Now I'm wondering what else they missed.....

[Rayd]

Does your car have an aftermarket blow off valve? and if so, is it set to 100% recirculate or does it have a trumpet for vent to atmosphere? if it is the latter, then that is your issue.

[Fever]

Does your car have an aftermarket blow off valve? and if so, is it set to 100% recirculate or does it have a trumpet for vent to atmosphere? if it is the latter, then that is your issue.

Na 100 % stock - I will double check in the morning. But the previous owner assured me it was totally stock.

[Rayd]

Ok I would check for boost leaks then

[Fever]

7

Ok I would check for boost leaks then

Using the bike pump method?

Or is using soapy water in a spray bottle ok?

Or is there actually a proper non cheapo way of doing this?

[lovecolt]

U will need a air compressor to pump pressured air into the system to check for boost leak. Do u have access to check the Afr ratio or the long/short term fuel trim of the car? And yes, I spent the same money with tune house and they did miss the most famous rear engine mount failure on my car.....there goes the expert of MPS....not

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[Fever]

U will need a air compressor to pump pressured air into the system to check for boost leak. Do u have access to check the Afr ratio or the long/short term fuel trim of the car? And yes, I spent the same money with tune house and they did miss the most famous rear engine mount failure on my car.....there goes the expert of MPS....not

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The car has an average fuel consumption on the dash? Haha

Lately its used a lot - but im planning to take it up the mountains or maybe down to The Gong this weekend. The drive might clean jt out a bit....think its been sitting around a while.

I have a mate at work who has some limited exp with turbos. He is going to check it out on friday.

Another guy suggested it might be a waste gate issues - releasing too much pressure/not shutting properly/shutting too slowly.

[shaneski]

You can try a battery reset, take both terminals off and pump the brakes a few times and then reconnect them, that will reset the ECU but it's best to baby it around for 50-100kms before thrashing it so the ECU relearns fuel trims otherwise fuel economy will be shit.

[Jmac]

Doubt it's a wastegate issue my money is on boost leak also

[Fever]

You can try a battery reset, take both terminals off and pump the brakes a few times and then reconnect them, that will reset the ECU but it's best to baby it around for 50-100kms before thrashing it so the ECU relearns fuel trims otherwise fuel economy will be shit.

Thanks mate I'll try that on Friday. Will give it a drive to the city nice and slowly.

And then boost leak checks on the weekend.

[AzzA SP20]

First check boost leaks.

Secondly I'm going to say you have a stock dump pipe with Both Cat's in place.
TBH this annoyed me alot when I first bought the MPS.
Even after few mods and tune was sill there, but going from an NA you notice it alot more.

Then I did dump pipe and in the process changed both cats to a single 200Cel unit.
issue totally gone (well to a point... its still a turbo car).

The stock dump is a very poor design with crap flow and large bottle neck with a lot of turbulence.
then you have 2 very restrictive cats just a few inches down from the turbo making things worse.


Im going to say Normal from your description, and you notice it heaps because you are use to NA.
Time for MODS!

But i always encourage Boost leak tests!

[Fever]

First check boost leaks.

Secondly I'm going to say you have a stock dump pipe with Both Cat's in place.
TBH this annoyed me alot when I first bought the MPS.
Even after few mods and tune was sill there, but going from an NA you notice it alot more.

Then I did dump pipe and in the process changed both cats to a single 200Cel unit.
issue totally gone (well to a point... its still a turbo car).

The stock dump is a very poor design with crap flow and large bottle neck with a lot of turbulence.
then you have 2 very restrictive cats just a few inches down from the turbo making things worse.


Im going to say Normal from your description, and you notice it heaps because you are use to NA.
Time for MODS!

But i always encourage Boost leak tests!

Yeah, I have driven 3mps and but did not experience the lag at all!

I have booked it in at MRT on Monday - hopefully they will be able to give me some advise and or diagnosis the problem.

[Fever]

So I just went for a drive with a mate in his 3 mps. He also drove my car.
it seemed like his was a lot more responsive - but it had a few mods (exhaust+intake).
The same lag was still there tho.
I guess the combo of mods+3mps makes more difference than I realised.
Also since I got a new top and bottom engine mount this seems to help too.

Sorry to be a noob and waste everyone's time

[SarcasticOne]

A good tune can go a long way to reducing lag

[Lachlan]

CobbAP + tune + flat foot shifting = 0 lag


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[Fever]

Haha, yeah ffs sounds appealing but idk if my clutch would agree