Rough low revs

[Dar77]

Hi, hope you're all well

I've recently turbo'd my gen 1 , running with a power commander 5 with 3 bar map sensor
Bigger injectors think 580cc
9:1 compression with base plate ,
Whilst running at low revs in between 2 and 3 thousand it's coughing and spluttering, I've tried taking fuel in and out in this rev range via the pc5 but makes no difference, if I turn fuel pressure down to 30 psi it seems to run a little better ,
Runs smoothly past 3000 revs and in boost
Has anyone else had this issue
Would a TRE help or is that not a good idea on boosted engine
Any help much appreciated
Dave.

 

[greg3852]

make sure you dont have any fuel leaks or sucking in air. thats what mine was doing and it would eventually sputter out

 

[202mphbusa]

Hi, hope you're all well

I've recently turbo'd my gen 1 , running with a power commander 5 with 3 bar map sensor
Bigger injectors think 580cc
9:1 compression with base plate ,
Whilst running at low revs in between 2 and 3 thousand it's coughing and spluttering, I've tried taking fuel in and out in this rev range via the pc5 but makes no difference, if I turn fuel pressure down to 30 psi it seems to run a little better ,
Runs smoothly past 3000 revs and in boost
Has anyone else had this issue
Would a TRE help or is that not a good idea on boosted engine
Any help much appreciated
Dave.

If you do not have a wideband you are guessing
I bet it is still rich in that rev range
What is your fuel system setup? mainly is your Regulator seeing boost and vacuum?
Most go Boost only, mainly because seeing vacuum, there tends to be a rich spike when you crack the throttle

 

[Hayabusa Wannabe]

Welcome @Dar77.

 

[Dar77]

I've checked all vacuum pipes for splits they are fine, no fuel leaks,

 

[Dar77]

I'll try fuel pressure reg just on boost side then , but yes it is seeing vacuum at the moment

 

[Busa Quick]

@Dar77

I recommend using the TRE on a Gen 1 Hayabusa because with the turbo system there is no RAM air, and your engine basically runs the same in every gear. It will also make the tuning a little more simple as well.

As far as I know, it affects the fueling as well as the spark timing. Suzuki had different maps depending on what gear you were in.

To be clear, the Gen 2 Hayabusa is different and the above information does not necessarily apply.

 

[Dar77]

If you do not have a wideband you are guessing
I bet it is still rich in that rev range
What is your fuel system setup? mainly is your Regulator seeing boost and vacuum?
Most go Boost only, mainly because seeing vacuum, there tends to be a rich spike when you crack the throttle

Had the afr set up on the Dyno it was spot on just swapped the pipe over from vacuum to regulator and run it straight off plenum, I'll keep you updated, if that makes no difference I'll order a TRE
Cheers guys
Dave

 

[Dar77]

Just been out unfortunately no change with swapping pipe from vacuum to plenum which goes to the fuel pressure regulator
TRE next port of call

 

[202mphbusa]

Just been out unfortunately no change with swapping pipe from vacuum to plenum which goes to the fuel pressure regulator
TRE next port of call

TRE will do nothing

 

[Dar77]

TRE will do nothing

Why because the power commander is overriding the ECU do you think?

 

[202mphbusa]

TRE only makes the bike ignore the sixth gear Mapping and rev limiters