Sunday, April 13, 2014 - 03:09 am, by: Blake Gloyn(Blakenz)
He polled a small group of friends/enthusiasts and was encouraged to do the compound.(innocent whistling from me) Compound is proven, it is easier to tune, cos there is no "swap over point", no complex valving on both the exhaust and the intercooler piping(the oneway valve required). Trying to get a sequential operation to work how you wish takes quite a bit of experimenting and time.
Sunday, April 13, 2014 - 04:50 am, by: Kurt Atzmuller(Kurt)
Like Blake said pipework is straight forward compared to sequential twins.
This is the way its done. You need to get the small turbo going as quick as possible to get to get plenty of energy for the gt 45 to fire earlier, that's the key.
I don't think boosting through the small turbo will be as bad as what people think. Velocity will be high as its already boosting and spinning at over 100,000rpm.
Otherwise setup with 2 intakes you'll have great initial response from the small turbo then a massive flat spot through middle revs and then the 45 would eventually fire at maybe 6000rpm. Thats not really the power curve i'm after.
Tuesday, April 15, 2014 - 09:25 pm, by: Kurt Atzmuller(Kurt)
That front wastegate is for the small turbo and will be plumbed back into feed the big turbo. there is another wastegate to control boost on the big turbo where you have pictured Allan.
Tuesday, April 15, 2014 - 09:26 pm, by: Walter Gillmore(Cl33pa)
Wut? Free up flow? Putting it there would clear space for moving the turbo forward. But it would also hit the engine mount. And the second wastegate would probably reside near that position. Outlet from first wastegate would merge into first dump there.
Friday, May 02, 2014 - 07:52 pm, by: Kurt Atzmuller(Kurt)
Haven't had much time to do much on this the last week or so but have modified this to this stage. still have to plumb the front gate back in and a gate for the big turbo.
Really need to get this small turbo in and try it out before i run out of time as tax time looms and is a busy time for me.
Wednesday, October 15, 2014 - 07:48 pm, by: Kurt Atzmuller(Kurt)
Got back onto this again after some dumps intakes and side projects... Here's some more pics!
Might even plumb in an airbox for this as i don't mind the look of it.
At the momment i'm plumbing the small turbo gate back in to feed the big turbo. And the 4 inch exhaust with giant flex joint will look cool!
You can see in this pic where the gate plumbs back in for the big turbo. Its a fairly tight squeeze past the water pump so a bit of heat wrap and it'll be fine.
Thursday, October 23, 2014 - 07:17 pm, by: Blake Gloyn(Blakenz)
looking real good,mate. there are a heap of clearance issues that you have to think through and overcome when you embark on something like this.Well done.
Friday, October 24, 2014 - 01:11 pm, by: Kurt Atzmuller(Kurt)
Yes there sure is Blake! Its a tight squeeze past the shock tower but it will be fine. Coming along real well though, will get the rear gate on this week and the big turbo oil return. Then on to the dump.
Wednesday, October 29, 2014 - 03:48 pm, by: Kurt Atzmuller(Kurt)
Need to build my 1.5j first to give it a real run. I will try it out first on my yellow car but it'll be a limited drive in that car.
I took it down to my tuner today and he was very impressed, his only concern was the small compressor housing being a bit too small and suggested getting it extrude honed to help it out a bit. Cost's roughly $200 for that so i will get that done before its up and running. He was a bit excited about tuning it all up and hasn't done one on a petrol engine so it'll be a learning experience for all!
Wednesday, October 29, 2014 - 06:43 pm, by: Robert Day(Lexsmaz)
Certainly will be an interesting thing to see it all work but I think even extrude honed if you look at the size of the outlet from the compressor side of the Big turbo to the size of the small turbo compressor outlet there are going to be some massive airflow differences / restrictions & heat once the big turbo kicks in hard ..
I think I mentioned a while ago if you put a by pass valve to the intercooler pipes at around where you have the open join from the big turbo to small turbo it might help ?? ..
My 2 cents worth, either way you have done a Very Nice job & keen to see how it all goes ..
Wednesday, October 29, 2014 - 08:28 pm, by: Kurt Atzmuller(Kurt)
I initially thought about the bypass too Robert but the more i look into it the more i think it goes against the compound purpose. Its a fairly tricky thing to get your head around how it will work but i feel now a bypass will give me a lower psi as a result.
Talking to my tuner guy at Dynomotive in vic about what pound springs to use and he thinks we will just try it out with the springs i have in there now which is 11psi on the small turbo and 14psi on the large one. He felt boost would be fairly high with those in there and we can change springs when we know where its at.
Its a 1 minute job to get either of the gates out so changing them wont be an issue.
I think now the small turbo will need a higher psi in order to flow the 45's boost through the comp better and with a hone and an extreme port out of that small turbo outlet should help things along.
Its all going to be fun though and really itching now to get my car going again now.
Wednesday, October 29, 2014 - 09:38 pm, by: Robert Day(Lexsmaz)
Trial & error definitely will tell but I was thinking if the by pass was set at about 7 PSI from the big turbo it shouldn't be too bad ??? as all / most of the initial spooling up help from the small turbo would well & truly done by then ?? ...
Either way you are certainly thinking out side the box & willing to share it with us ..