76 replies to this topic

[FLD]

 

Surely there's a factor of on / off where the compressor wheel is moving an amount of air (in a givien efficiency) which is different to what the engine is 'drawing' in.  If the engine is pulling more air than the compressor moves then its off, once the compressor moves more then its on?

 

Yep, that how I understand it, it's a closed loop feedback circuit. However, remember that once it's "ON" fully the wastegate should open to stop the feedback system escalating infinitely.

 

 

Have a look at the Holset turbo's with the sliding ring VGT system Nev.  I really like those.  Big in the US but not so popular here. 

[Winstar]

 

 

Surely there's a factor of on / off where the compressor wheel is moving an amount of air (in a givien efficiency) which is different to what the engine is 'drawing' in.  If the engine is pulling more air than the compressor moves then its off, once the compressor moves more then its on?

 

Yep, that how I understand it, it's a closed loop feedback circuit. However, remember that once it's "ON" fully the wastegate should open to stop the feedback system escalating infinitely.

 

 

Have a look at the Holset turbo's with the sliding ring VGT system Nev.  I really like those.  Big in the US but not so popular here. 

 

 

Let me know if you want to know what truck to get one off

 

PS the turbine or compressor will choke rather than escalate infinitely

[denno]

The turbo you mention simon is that similar to the gt2871r? I'm not looking for anymore power just looking for improvements on my current setup and I believe the Garrett would e more efficient compared to the k04.Think id kill myself with 400hp

What is it you feel is missing from your current set up?

[Bumblebee]

Better spread of power

[techieboy]

Sequential turbos. Accept no substitute. Other than a supercharger, of course.

[siztenboots]

Better spread of power

whereabouts on the rpm range

[rob999]

Compound charging is the only answer.

[FLD]

Compound charging is the only answer.

 

No its not.  VNT or VGT can give boost at tickover and then right through the rev-range.  For example, Geoff Kershaw runs a twin VNT turbo sierra in hill climbs and this has 3psi at tickover.

[Winstar]

Better spread of power

 

Spread of power will always be limited by the amount of map width you can get on a compressor,better mapping and boost control will make the most of what the turbo can do but the rev range on petrol engines is too wide to use a single compressor. So quite simply unless to use sequential turbos or twin charging your going to have to make a sacrifice at the top end (as per the std turbo) or low revs with bigger one.

[Bumblebee]

Compound charging is the only answer.

No its not. VNT or VGT can give boost at tickover and then right through the rev-range. For example, Geoff Kershaw runs a twin VNT turbo sierra in hill climbs and this has 3psi at tickover.

Yep my dad's noble is running twin vnt turbo's,drives just like a v8,everything's instant at any gear I.e next to no lag

Edited by Bumblebee, 01 October 2013 - 04:06 PM.

[Winstar]

 

Compound charging is the only answer.

 

No its not.  VNT or VGT can give boost at tickover and then right through the rev-range.  For example, Geoff Kershaw runs a twin VNT turbo sierra in hill climbs and this has 3psi at tickover.

 

 

VNT will give you the power to drive the compressor to where you want it but for a road car finding a map that will produce a 2:1 PR from 1000 - 7000 rpm is going to be very hard. Holset/CTT maps are the widest there are and the calcs I did on a 2.2 would only get from 3000 - 7000, one of the HBLS wheels may have worked but they don't do them small and need to be Titanium to take the stresses.

[Bumblebee]

I'm happy with my current setup but was just looking for improvements I.e the k04 comes in quite strong/sharp and wondered if the gt28 could make it come in power better with the right mapping

Edited by Bumblebee, 01 October 2013 - 04:03 PM.

[Thealastair34]

I run that turbo but on a 1600 engine, I'm running the larger housing so more lag than the smaller, I'm full boost at 4.5k and its making around 7psi at 4k iirc I can only imaging the increased displacement reducing your lag, I'll post a pic of my graph. I wanted peak power on the limiter which is what I specced and built the engine for and it delivers it at 8k Funny enough I'm looking for more development over winter so I'll sell you the 28 if you want

[Bumblebee]

I've actually already bought the gt28 just need to decide wether to fit it or not..........

[Rickwoo118]

I've actually already bought the gt28 just need to decide wether to fit it or not..........

Aimy, if you have it already just get it fitted. I am sure it will be better than the K04 as it's on its limits at the moment. If you did fit it apart from the turbo what else are you thinking of changing/ upgrading? I am sure you don't want to go big bhp like Dave H etc ...surely you want more than 300 bhp?

[Bumblebee]

I'm limited with power on the standard internals anyway Rick but I'm happy with around 300hp give it take tbh. My thinking with the Garrett was, running similar power to now but at lower boost Gaining more top end (although I've been told I'm limited to 7200rpm by one person but then another person said this is too high for my internals) The turbo will spool up nicer but will maybe come on boost later? I'm looking for better drivability but I'm struggling for concrete answers tbh as I'm getting different opinions which I guess is understandable as this stage is maybe a bit unknown

[Bumblebee]

I've also got a klassen manifold

[Rickwoo118]

I'm limited with power on the standard internals anyway Rick but I'm happy with around 300hp give it take tbh. My thinking with the Garrett was, running similar power to now but at lower boost Gaining more top end (although I've been told I'm limited to 7200rpm by one person but then another person said this is too high for my internals) The turbo will spool up nicer but will maybe come on boost later? I'm looking for better drivability but I'm struggling for concrete answers tbh as I'm getting different opinions which I guess is understandable as this stage is maybe a bit unknown

What about giving John at CS a call and ask his opinion? It's only a phone call? I can see the reason why you are thinking of doing it. If it was me I would be looking at extra horses and torque though if i was spending all that money. Interested what you do in the end as it may give me some ideas.

[ArticMonkey]

All what you say points to one thing, and that's the way it's mapped. If you want more control and usability then the staandone unit George and Dave have is the only option. I'd also take Geroge up on his offer as I think you need to find that sweat spot before you spend out. Ideally you could do both map and turbo and have multiple maps for driving to work or fast road/track.

[Thealastair34]

I wouldn't bother without doing the rods and pistons then and being able to make the most of the turbo and the engine revs If your going to do it then you might as well go the whole hog like the rest of your car In reality it will make naff all diffenrce on the road as you cannot exploit it but I understand that you want to build or own something special and put your mark on it