Jump to content
Please check your junk folder for registration emails ×
  • Current Donation Goals

    • Raised $0.00

Why "stock location" always disappoints


boon

Recommended Posts

  • Admin
41 minutes ago, Loren said:

I thought it was common knowledge that the stock location equivalents were much smaller and therefore not the real deal? Maybe I'm just a clever clogs.

 

Well, the compressor and turbine wheels are the same (same CHRA) but the turbine housing is where it all goes horribly wrong, in my opinion.

Link to comment
Share on other sites

The inlet size is going to hurt... 2 inch vs 4 inch! But also, I can't help thinking that the stock location turbos are designed to spool faster

and give a more stock like feel, but with extra power? It would be a bit of a shock for most people... though the yanks have 2.5 litres anyway, so maybe not such an issue.

Edited by Loren
Link to comment
Share on other sites

Stock location turbo on a USDM doesn't have the brake booster etc in its way does it? Wouldn't that give them heaps more room to fit a big arse (ass in American) turbo.

 

as for your theory on high back pressure since the pairs of heads are out of phase the high in one is the low in the other.

so won't the pressure not back flow into the cylinder but rather equal out into the other header where the valve is closed and there is less gas.

F***ed if I explained that well, most likely not.

 

twin scroll is about having multiple pulses of gas combine to create higher pressure, kind of like resonance you get more rpm from the turbo from less gas. In the low pressure phase the turbo is happily freewheeling.

Link to comment
Share on other sites

One thing I notice on the American forums for stock location big power turbos is they seem to using the FP black series turbos.

I don't know much about these, but is it that they run these turbos instead of Blouch/Garrets that allows them stock location and big power? Are they designed to fit stock location and still produce big power?

Also not having the brake booster could allow for a bigger turbo by having more room around it to reposition enough to fit?

Any reason we don't see the FP series turbos here? is it just cost? They seem to be the main flavour of turbo for big power in the US

Link to comment
Share on other sites

  • Admin
12 hours ago, Gripless said:

Stock location turbo on a USDM doesn't have the brake booster etc in its way does it? Wouldn't that give them heaps more room to fit a big arse (ass in American) turbo.

 

as for your theory on high back pressure since the pairs of heads are out of phase the high in one is the low in the other.

so won't the pressure not back flow into the cylinder but rather equal out into the other header where the valve is closed and there is less gas.

F***ed if I explained that well, most likely not.

 

twin scroll is about having multiple pulses of gas combine to create higher pressure, kind of like resonance you get more rpm from the turbo from less gas. In the low pressure phase the turbo is happily freewheeling.

 

Yes and no; the lack of a brake booster etc means they can play very fast and loose with the term "stock location" and have the downpipe end up way out there, which we obviously can't do, giving them the option of reasonably large turbine housings.

 

The exhaust pulse thing only really works when you have a good flow out the exhaust (NA or huge turbine housing) - otherwise the entire pre-turbine exhaust tract is under pressure anyway. Think of it like blowing up a rubber glove; all the fingers will have more or less the same pressure in them. There will be localised pressure differences due to valve events but the speed your exhaust travels means they won't be huge.

 

I don't think you get a whole lot of freewheeling in a turbo with your foot up it; I don't think they would last long if you did. Likewise in practice, especially with a piddly little turbine housing, you don't have much of a low pressure phase. The analogy I would use is if you had a huge funnel with a hose coming off it and you tipped water into it in bucket-fulls; whilst you might be filling the funnel with pulses the output through the hose will be more or less continuous and consistent. If you were able to get your exhaust gasses out of the turbine so fast that you had periods where there was no turbine flow you would never build any backpressure, whereas people who have actually tested EGBP on these cars find it regularly exceeds 2:1 of the intake pressure.

Link to comment
Share on other sites

Can't compress water which is why the funnel doesn't work.

 

but your taking extremely short time frames "freewheeling" between pulses and like sound waves are just compression waves.

but the pulse thing is why twin scroll exists, I'm sure there is a YouTube video of that side that involves a pinwheel.

 

also what's the octane on American fuel there maybe a difference there too.

Is there compression difference in the USDM model compared to what we have here?

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recent Status Updates

    • MrSg9Sti04

      Afternoon team,
      im new to the group first time posting. Im hoping some body can help me get my launch control all dialled in on my link g4x. Ive had the computer and car all tuned from chris at prestige awesome knowlegable guy super happy with the results but now im wanting to get my launch/anti lag all dialled in. Ive been reading multiple different forums etc all with different conflicking information which has made me nervious with what do i listen to this or that if you get what i mean. Now ive started to make myself familiar with my PClink software etc the past few weeks and im eager to learn how to do minor setups or tweaks etc so im not relieing on my tuner so much and obviously saving myself abit hurt in the back pocket. 
      Now back to the question at hand.... Im wondering if theres and one who could please share there knowledge and wisdom with setting all my values, timing, fuel etc when i have launch control armed and engaged, or even a launch tune file they can possibly send me to load onto my tune. Ive figured out the setup of my digital inputs turning launch control on etc and its obvisously on its pre set factory settings. It engages but doesnt sound the greatest or as angry as it should i feel. Hence reaching out to you good buggers. 
       
      Cheers in advance for any info and help yous maybe able to give me.
       
      Cheers Shaun
      · 0 replies
    • Joker  »  gotasuby

      updated your DP's too : hope that's ok!
      · 0 replies
    • Joker  »  SAS

      Updated your DP's to reflect your business page  
      · 0 replies
    • Joker  »  Nachoooo

      Updated your Avatar : couldnt help myself  cheers!
      · 0 replies
  • Recently Browsing   0 members

    • No registered users viewing this page.
  • Forum Statistics

    40.9k
    Total Topics
    573.5k
    Total Posts


×
×
  • Create New...