Gcg Xr6 Turbo Upgrade

[youngy]

kostecki actually make billet oil pump gears here in the west now (were'nt available when I rebuilt my engine) and I believe they can be had at a reasonable price compared to what nizpro charge.

I'm more interested to see how much bottom end and mid range power would be sacrificed with the enlarged turbo over the gains made in top end with this upgrade

←

Kostecki have some for me mate! woo hoo!

←

good on ya. how much?

now hurry up and do this gcg upgrade and let me no if its worth while lol

[Romulus]

Here's some interesting reading about upgrading turbos. It explains how 1 turbo can make more power than the other running the same boost. Taken off LS1.com.au of all places where I hang out with my 5 mates

This kind of stuff makes me laugh at cars running 20+ psi on the stock turbo.

"Ah the boost pressure to power ratio question again... FST57L did a good job of explaining it.

Basically mass flow rate and hence volumetric efficiency are improved with larger/better turbo chargers… Boost equal. 10psi is not 10psi in mass flow rate terms. Looking at one element such as boost pressure is not looking at the whole picture.

Boost pressure is the force applied to the walls at a tangent to the flow of the air mass; it isn't a direct measure of mass flow. It can be a variable in it, but it’s not the factor by which mass flow rate is judged- it is only one part. What is a hard concept for some is the affect of a turbocharger on the engine system. You need to understand that volumetric flow rates increase with larger turbo chargers and forget the pressure ratios they run at.

It’s to do with increased volumetric efficiency of the turbine section and housing plus the interaction of exhaust backpressure to intake boost pressure. The By far the single biggest effect of the larger turbo is reduced back pressure to intake pressure ratio and lowering of exhaust manifold pressure. This combined with other factors including increased engine operating speed all lead to greater mass flow rates at equivalent 'boost' pressure ratios hence you have more power with a better/bigger turbo(s)."

Edited 24/07/06 02:01 PM by M6 XR6T

[Ralph Wiggum]

hmm nice. you probably could have just summed it up by saying bigger turbo's flow more air (in and out) than smaller ones at the same boost pressure...

[F6 UTE]

Yes Jason, bigger turbo, more volume for less psi. Simple theory.

What about restrictions in the system, other than exhaust back pressure, like intake restrictions, intercooler efficiency, resonant frequency of the intake manifold, cam duration etc?? All lacking in a stock xr6 turbo setup.

The system will flow as much as it can, ie VE, regardless of what pressure that is pushed at. Lower psi, less heat, more power yes.. Better intercooler, lower charge temps, less restriction, more power.

And how many guys actually upgrade there exhaust manifold, before they bolt on a bigger huffer??

How many guys get the stock engine running at maximum efficiency, or increase the volumetric efficiency to over 100%??

Not many I gather.. But bigger must be better, even if it sacrifices drivability for some extra top end, where it might spend 5% of it's life..

If you're pushing the factory turbo to it's rated top end, the extra 50hp might be worthwhile, otherwise, bolt on a bigger ( substancially ) turbo.

1.5 cents anyway..

Just adding to this..

Turbos are designed to push boost, it's there job. Generally, all turbos have a sweet spot. The point where they make the most power Vs heat for said boost pressure used. My last TD05 16g ran 19/20 psi. It loved it, and the point at which that turbo was considered to be at it's optimum poit, 17.5 psi. Max power was seen at 23psi. I had a good cooler, rated to higher cfm that the turbo could push, and appropriate ancillaries to cope. A good combination.

I have no doubt that the XR6 GT setup would be comfortable around 20 psi, maybe 22 manifold, with a non restrictive setup.. .. at a guess. Based on max hp and boost needed to achieve it's rated hp figure.

20psi aint big boost. 29-40psi is boost..

the other .5cents..

Edited 24/07/06 02:49 PM by F6 UTE

[Ralph Wiggum]

[youngy]

I agree. that's where I believe this could be a good mod for ppl like f6 rapid and I who have built engines and are at the standard turbos limit and are hunting for a cost effective way to gain some top end without sacrificing much bottom end and mid range. I'm chasing 600rwhp on pump fuel, I could get it now on race fuel but it's a daily driver and too impractical. The other option at $5500+ is the nizpro turbo and manifold upgrade which comes with a long wait and I suspect won't make substancially more power than this $1850, 4 day turn around option.

[F6 UTE]

If you're chasing a bit more top end, why not consider a lower manifold change. I doubt your at the max of the factory turbo juuuuust yet..

You can add a bit more top end with shorter runner length, effectivly 'tuning' the engines powerband for your requirements. I alluded to this in Goldbullets thread on his Nitto manifold. Might be tricky with the Nizpro lower half, but quite feasable..

6boost have some BA exhaust manifolds at ~$1300, with a merged collector setup, and look good value for money. I'm sure a T3 flanged turbo would not set you back $4k if you shop around, or get one in from the states.. Weld up the internal gate, weld in an external ( 6boost can supply flanges in there manifolds ) off you go..

[F6 RAPID]

I agree. that's where I believe this could be a good mod for ppl like f6 rapid and I who have built engines and are at the standard turbos limit and are hunting for a cost effective way to gain some top end without sacrificing much bottom end and mid range. I'm chasing 600rwhp on pump fuel, I could get it now on race fuel but it's a daily driver and too impractical. The other option at $5500+ is the nizpro turbo and manifold upgrade which comes with a long wait and I suspect won't make substancially more power than this $1850, 4 day turn around option.

←

I am with you mate.

This mod would actually do me...........I think.............for a while................maybe.

I am going to change all my piping from the turbo compressor through to the inlet to 3 inch the whole way - including welding new ends on my Nizpro 'cooler. This mod coupled with the turbo mods will make (I believe) a pretty marked improvement. I want 450-500rwkw's on pump fuel - same as Youngy. Dyno days, track days and the like, I will throw some Sunoco in it just for good measure and run a race tune.

The only problem we have Youngy, is making Simon get one and tune it for us first - at least I do being over here with no-one to tune it otherwise!! So, will you hurry up and do it for me, go on, you know you want to.....

[youngy]

If you're chasing a bit more top end, why not consider a lower manifold change. I doubt your at the max of the factory turbo juuuuust yet.. 

You can add a bit more top end with shorter runner length, effectivly 'tuning' the engines powerband for your requirements. I alluded to this in Goldbullets thread on his Nitto manifold. Might be tricky with the Nizpro lower half, but quite feasable..

6boost have some BA exhaust manifolds at ~$1300, with a merged collector setup, and look good value for money. I'm sure a T3 flanged turbo would not set you back $4k if you shop around, or get one in from the states.. Weld up the internal gate, weld in an external ( 6boost can supply flanges in there manifolds ) off you go..

←

The 6boost exhaust manifolds are they a direct replacement and do they have a website?

Also I have the nizpro top half of the inlet manifold and just the stock lower half is there any proof that modifying the lower inlet manifold will work, I know simon milled his one out and it didn't do a thing. I can see how the exhaust manifold could make a big difference however.

If I knew this turbo upgrade wouldn't sacrifice much bottom end and mid range I'd order 1 tomorrow. I just don't want a laggy car and like the way I can fry the tyres at will when ever I like

[youngy]

hmm nice. you probably could have just summed it up by saying bigger turbo's flow more air (in and out) than smaller ones at the same boost pressure...

←

lol yerrr reminds me of first year tech on hydraulics, After all a turbo is just a pump. Ahh those were the days...