Reducing Lag

[popsy09]

I'm using a vf34 dude not the most responsive turbo I must admit lol.

but you do get used to it at first with the td05 i was saying i made a mistake but man i loved it and people who were in my car and drove it said the same


just make sure your in the right gear at the right time that was my motto lol

 

[Corey_gt]

Ya you defo get used to it alright dude you have to drive them in different way but it becomes the norm to you after a bit of time.

 

[popsy09]

Ya you defo get used to it alright dude you have to drive them in different way but it becomes the norm to you after a bit of time.

when you start pulling on a big hp evo or scoob etc top end you know its worth it ha ha

 

[AdamB]

Variable vane turbochargers?

 

[ramses974]

yea higher comp is quicker response on na but when trying to spool a big turbo lower comp is better im pretty sure

not in my case , it is not easy to spool a big turbo with a low compression turbo,but very very easy when it is high compression
My new set up is a come back to my first set up, 5efHe High->forged high compression pistons

 

[98_glanza]

not in my case , it is not easy to spool a big turbo with a low compression turbo,but very very easy when it is high compression
My new set up is a come back to my first set up, 5efHe High->forged high compression pistons

ya as far as i know,higher compression = better spool times

 

[98_glanza]

out of interest what compression do ye 4e high compressioners get on each cylinder?

 

[Gord R]

Variable vane turbochargers?

I am surprised no one has commented on this yet.

 

[AdamB]

Porsche have been using them for years, and there just coming into F1 in the next few years.
I know how they work but not 100% how they are controlled, that may be the limiting factor.

 

[Texx]

I am surprised no one has commented on this yet.

I've got a GT1752V sat here that I keep threatening to have a play with.

I know how they work but not 100% how they are controlled, that may be the limiting factor.

Controlling the vanes is the difficult bit, you can't just use a basic open or closed approach as the compressor will surge when the engine is at low revs and under little load. I've been spending some time thinking how I could get some functionality from it, but there's still some thought required before I make any attempt to bolt it to the car.

 

[AdamB]

I thought maybe some sort of centrifugal weights or an actuator to move the vanes? I'm not sure how Porsche control theirs, maybe could do a bit of research and copy their method.

 

[Gord R]

I've got a GT1752V sat here that I keep threatening to have a play with.

I read somewhere that running diesel vvt's on petrols can cause problems. Any thoughts?

 

[Texx]

I thought maybe some sort of centrifugal weights or an actuator to move the vanes? I'm not sure how Porsche control theirs, maybe could do a bit of research and copy their method.

That's not quite what I meant, the actual mechanics of operating the vanes isn't really an issue, it's the control of the mechanics that's the problem. Opening and closing the VNT like you would a conventional wastegate won't work, the position of the vanes would need to be constantly monitored and adjusted based on a combination of engine RPM, throttle position and manifold/compressor pressure. For it to work successfully, it would require a custom made programmable control system and you'd also need an external wastegate to limit maximum boost.

I read somewhere that running diesel vvt's on petrols can cause problems. Any thoughts?

I know the older designs like the VNT25 weren't very reliable, however the newer generation GT series VNT turbos appear to be a little more robust. But to be honest until I've actually tested one on a petrol engine I wouldn't like to comment on the reliability.

 

[Gord R]

What sort of top end power / responce are you hoping for Texx?

Sorry to hijack the thread by the way!

 

[corofin12345]

found this and thought id throw it up.. interesting to say the least

[video=youtube;KgVrpiFfp8U]http://www.youtube.com/watch?v=KgVrpiFfp8U&NR=1[/video]

 

[Texx]

The GT17 isn't very big, so I wouldn't be expecting huge numbers 200HP would probably be the limit in terms of airflow. However it has the potential to produce 120CFM@1Bar by approx 1500rpm, so hopefully it'll be quite responsive if I can get it to work.

 

[Rev]

The GT17 - it has the potential to produce 120CFM@1Bar by approx 1500rpm, so hopefully it'll be quite responsive if I can get it to work.

Texx I am wondering how that works? - I have put a few figures in squirrel and see
http://www.squirrelpf.com/turbocalc/

180hp 107cfm 21.7psi at 2000rpm peak power 5500 rpm
200hp 120cfm 40.6psi at 1500rpm peak power 4000 rpm
250 hp 121cfm 40.6psi at 1500rpm peak power 5000 rpm

x2 the Starlet engine volume is the limiting factor rather than the GT17. Using 'squirrel' it looks like the engine cfm at 1500 is less than 120cfm ?