HELP... 3" TIP boost surge?!

[J@mes]

Hi people, want to pick your brains, I noticed yesterday whilst driving my car since I have fitted my 3" SFS TIP, between 2 - 3k rpm if I floor it in 3rd gear or above I get boost spike, as in I hit about 27psi and the boost gauge needle flickers from 26-28psi really quickly on WOT and you can hear this flutter sound, which I believe from research is called boost surge. Also from research I have found a few people have had this problem since fitting a larger bore TIP and to fix the problem you either need your map tweaked or a MBC (fitted in line with the n75) to cap the boost, has anyone else also found this after fitting a 3" TIP? From research I think Samuel Bryant did?

I never had this problem before with my Jabba stage 2 LCR, and it has since come from fitting the 3" TIP and thus shows the TIP is working allowing the turbo to suck harder, but I think I need my map tweaked but I will prob go down the route of MBC I think due to cost mainly and it being far less hassle than day off work and driving back to Jabba etc etc.
Also I don't know about other peoples cars but I always find in the summer/hotter weather my car always boosts a couple of psi more, AFAIK that's the ECU compensating for the hotter weather and trying to create the same power by upping the boost. So I am thinking that once summer is over and the temp is cooler I prob wont get this boost surge I am now seeing, but to be on the safe side its prob worth me getting a MBC to cap boost so I dent bend a rod or something. This is all assuming the few hours research I did last night is correct and a MBC is an ok way to deal with the problem I now face?

If so will this MBC be ok? http://cgi.ebay.co.uk/ws/eBayISAPI....akeTrack=true&ssPageName=VIP:watchlink:top:en
How does it compare to the Forge unos one apart from not looking as shiny and only costing £20, £60 odd cheaper than the forge one.


Cheers everyone! =)

 

[J@mes]

bump!

 

[ibizacupra]

no experience of the ebay mbc but unos works well.. and easily adjusted.. plumbed in parallel it can clip the spike (which is excessive imho) - hope you have rods..

engine once past 4200rpm can take more boost but the spike a lot of maps have ask for more air than the engine can take (with the high flow tip), and you cross the surge line.

mbc in parallel with n75 will allow you to adjust the spike level to a level where it does'nt flutter and surge.

also make sure your dv has a decent spring in..

 

[J@mes]

Thanks for the advice Bill!

I have a yellow spring and one shim in my 007 DV for what its worth. Think I will do a service on the DV soon too, as I have not done one on it for a while now!!


Out of interest, if you were to adjust the map, how long out of interest would you estimate it would take?

Cheers.

 

[ibizacupra]

I would allow 1/2 day for adjusting...
depends on what jabba have done for a map as to what I can do... and just as likely just redo one from scratch

 

[J@mes]

ok bill thanks for that, I will bear it in mind.

 

[J@mes]

Hi Bill,

Quick question, will running a MBC in parallel with the n75 to cap my boost spike effect my MPG at all? I wouldn't have thought so, but I read somewhere that using a MBC to reduce boost made your MPG worse on part throttle. Sounds like bs to me, well I certainly hope so!

Thanks,

James.

 

[ibizacupra]

sounds unlikely to me.. why would that be? it caps boost... not adding anything

 

[J@mes]

Thats what I thought. The explanation I read was because the MAF reads more air than what the turbo is getting so over fuels?!

 

[J@mes]

Thats what I thought. The explanation I read was because the MAF reads more air than what the turbo is getting so over fuels?!

Also Bill, when fitting a MBC in parallel, once plumbed in is it just a case of driving the car and looking at my boost gauge, and then adjusting the MBC until I cannot boost more than say 24psi if that's what I want to cap it to?

Just wanted to double check!

Cheers.

 

[ibizacupra]

yep

 

[8bit]

Sorry for thread hijack but I'm getting a similar thing. No boost gauge but on the dyno boost hits 27psi about 3800rpm and I get the flutter noise, worse in higher gears.

J@mes, did you get your MBC fitted yet? If so, have you set it up? Any reduction in performance once you got the boost capped?

@Bill, I know there's more to it than this but what would you consider a more sensible peak boost on stock internals? My car is 55-plate, 64k miles, only mapped about 3k miles ago.

 

[J@mes]

Funnily enough I am planning on fitting it tomorrow!

As it is only capping boost (for arguments sake lets say at 24psi) performance wise when going flat out through the gears it shouldn't effect the performance at all as you wont boost as high as that when the revs really build up, but when driving more normally and say going WOT in 4th gear at a slowish speed as the boost builds up the MBC will stop you going over 24psi, so yes you will loose a slight amount of power/torque but the turbo will be happier/safer and you will eliminate the flutter!

Well this is what I am assuming, will find out soon hopefully!

 

[ibizacupra]

Sorry for thread hijack but I'm getting a similar thing. No boost gauge but on the dyno boost hits 27psi about 3800rpm and I get the flutter noise, worse in higher gears.

J@mes, did you get your MBC fitted yet? If so, have you set it up? Any reduction in performance once you got the boost capped?

@Bill, I know there's more to it than this but what would you consider a more sensible peak boost on stock internals? My car is 55-plate, 64k miles, only mapped about 3k miles ago.

22psi cap personally.. cap it there on stock bottom end (this is what I did on samb lcr on his stage 2 cc when it spiked high)

25psi+ spikes make me very nervous personally

 

[8bit]

22psi cap personally.. cap it there on stock bottom end (this is what I did on samb lcr on his stage 2 cc when it spiked high)

25psi+ spikes make me very nervous personally

Thanks Bill. I take it if I set the MBC to cap at a lower value than the map requests I risk hitting limp mode and boost leak codes? I've got Revo stage one so I can adjust the boost setting, I just don't know if the adjustment on the map is a simple percentage change under all conditions or if its' intended to reduce sustained boost or spike. They never got back to me when I emailed either.

Funnily enough I am planning on fitting it tomorrow!

As it is only capping boost (for arguments sake lets say at 24psi) performance wise when going flat out through the gears it shouldn't effect the performance at all as you wont boost as high as that when the revs really build up, but when driving more normally and say going WOT in 4th gear at a slowish speed as the boost builds up the MBC will stop you going over 24psi, so yes you will loose a slight amount of power/torque but the turbo will be happier/safer and you will eliminate the flutter!

Well this is what I am assuming, will find out soon hopefully!

Nice one, cheers J@mes. Please keep me posted? I sort of figured that altho the boost peaks at about 3800rpm the torque isn't peaking until almost 1000rpm later so even tho the boost is high low down the car can't be using it properly.

 

[ibizacupra]

it should be ok... capping it at 22psi is 2550mb near as dammit so the limit of map sensor being able to read it anyhows... so the overshoot it has now does'nt limp it, so clipping it wont either

 

[Harris.]

Does anybody fit electronic boost controllers on these cars with the k04? I have a couple of friends that runs them on mk1 focus rs's and they swear by them. They say you can cap it like a mbc and run lower boost for normal driving conditions. They just leave their boost solenoid connected so the ecu still sees it.

Sent from my HTC Sensation XE with Beats Audio Z715e using Tapatalk 2

 

[ibizacupra]

yes.. fitted several.

whether the cars map, depending on who did it will cause limp mode however is going to vary between tuners maps

 

[Harris.]

I did wonder that. Thanks for that Bill.

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[8bit]

it should be ok... capping it at 22psi is 2550mb near as dammit so the limit of map sensor being able to read it anyhows... so the overshoot it has now does'nt limp it, so clipping it wont either

I figured that the Revo software would have to disable the standard ECU boost limit so the car didn't just throw limp and overboost codes, just assumed that they'd leave in the lower limit for deviation vs. request so the car could still ECU could still see boost leaks. Heard of one guy found that he got limp mode with an MBC, maybe I was wrong but I'd assumed he'd maybe capped it significantly lower than the request.

In any case, as I said in my RR I found some logs and checked those, never seen actual boost go above 2550 on the road so I'm now not sure that value on the RR graph is correct. Going to install a boost gauge before deciding if I need an MBC.