Gcg Xr6 Turbo Upgrade

[RAP1D]

Sorry to dig up an old thread but...

Now, say we put the GCG turo on a car that was running 300wkws on 14psi, just a simple set up with the usual IC/edit/injectors ect done.

Could we expect ot see the same 300kws at less psi, say 10psi? If so, and I dont see why not, this would be a much safer and much more "kinder on the rods" way to achieve 300kws.

That being the case, would 350wkws on 14psi be achievable on a stock bottom end, being that too much psi bends rods.

Im not after 400plus kws, but a safe 300 at 10psi would make me blow 2k on a turbo anyday.

[Romulus]

Sorry to dig up an old thread but...

Now, say we put the GCG turo on a car that was running 300wkws on 14psi, just a simple set up with the usual IC/edit/injectors ect done.

Could we expect ot see the same 300kws at less psi, say 10psi? If so, and I dont see why not, this would be a much safer and much more  "kinder on the rods" way to achieve 300kws.

That being the case, would 350wkws on 14psi be achievable on a stock bottom end, being that too much psi bends rods.

Im not after 400plus kws, but a safe 300 at 10psi would make me blow 2k on a turbo anyday.

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There's no reason why that shouldn't work.

Too much psi in the midrange kills rods.

[Ralph Wiggum]

hhhmmm. ..what kills rods too much boost in the midrange or a tune that allows/causes detonation in the midrange..?

[F6 UTE]

Boost AND detonation kills engines. The weight of the car is of no help either.

External gates, ebc's and mbc's all have maximum boost at the earliest possible time, tapering off gently in the later rpm.

This has been the case since, well, as long as I know.

The fact we ( tuners ) can tune/control boost per rpm is relativly newish, guys just need to get used to the idea that boost is good, unless it's in the top end, imo.

If boost in the midrange kills rods, why don't cars go bang when they are on stage, at the lights?? All stalled up, making boost and power.??

An engine is more likely to go kaput on decel on a dyno, when it runs lean.

Anyone ever taken much notice of big ( I mean BIG ) HP cars, allways get the throttle blipped on decel after a dyno run.....

[RAP1D]

Yep, too much boost at low rpm is a common rod bender in many cars. I know a few guys in the states that bent rods on 20psi and slight detonation from little TD04's in volvo 850R/T5-R's... Vr4s are common rod benders too

[Romulus]

External gates, ebc's and mbc's all have maximum boost at the earliest possible time, tapering off gently in the later rpm.

This has been the case since, well, as long as I know.

This is more likely due to the turbo running out of flow, rather than a desired tune or result.

On the contrary, I've seen plenty of turboed cars run moderated amounts of boost in the midrange and steadily increasing by a couple of psi to peak rpm. Nice power and torque curves too.

The fact we ( tuners ) can tune/control boost per rpm is relativly newish, guys just need to get used to the idea that boost is good, unless it's in the top end, imo.

If you like power and torque characteristics of a turbo diesel engine, then this is the way to go. I have it on good advice by one of Australia's leading tuners that too much mid range boost accompanied with detonation and/or lean mixtures is the #1 cause of XR6T engine failures.

MkI XR6T manuals don't like heaps of midrange torque as it causes trans failures. By limiting boost in the midrange and increasing it at the upper rpm the engine can make quite reasonable power, without the risk of popping the trans.

If boost in the midrange kills rods, why don't cars go bang when they are on stage, at the lights?? All stalled up, making boost and power.??

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Load is what is missing from your point. Usually, cars that run high boost and lean mixtures in the midrange usually pop an engine as soon as a gearshift at WOT has been executed. Auto's especially are prone on the 2-3 gear shift, as boost momentarily flares up a couple of psi. That with a momentary lean out ends up in tears for some people.

[XRDRIFT]

Im no turbo tech guru at all, but been reading this thread with much interest. Cant remember the turbocharger combo that GCG is offering, but I'm looking to achieve a max power lvl of 310 or so rwkw's. A point that RAP1D made.

But I read that a car running 14psi with 300rwkw becomes too violent and hard the engine internals as a daily driver so would the gcg turbo be a good choice to get the same lvl of power at lower boost levels. As I dont want to build my "T" and its unsafe at high boost when theres an option to get same amount of power using less amount of psi. Not taking away the option to run more boost if just doing a fast run down the 1/4 mile to get a good time.

Is it worth my while looking into it? The car will be used occasionally for drifting, track days and a few runs down the 1/4 mile. Not going out to break any records just a driveable, reliable fast car. Will keep following this thread with much interest to get more info, and get some turbo education.

[xlnt6]

Could we expect ot see the same 300kws at less psi, say 10psi? If so, and I dont see why not, this would be a much safer and much more "kinder on the rods" way to achieve 300kws.

The answer is not as simple as it seems. You need to consider that the factory turbo is rated at 600HP (450kW). What that means is that at 300 rwkW the turbo is operating well within it's efficient operating zone (look at a Garrett site and check out the compressor efficiency lands).

When you push the turbo in an effort to gain HP, you need to look at what impact this has on the efficiency and how close you are to the maximum flow capability of the turbo. What you'll find as the demand for HP increases the turbo falls outside the efficient zone and as a result:

(a) you need to increase boost pressure (but you don't realise an equivalent increase in flow rate)

(b) outlet temps increase

© engine timing needs to be removed to compensate.

At that point it's time to change the turbo spec so you are back in the efficient operating zone. The result is, less boost pressure, reduced outlet temps and ability to support more timing advance.

So, if you want to cap power at say 310 rwkW (say about 380 fwkW), then you can safely do so with the stock turbo. The stock turbo will be efficient at this point, and so the benefit of the larger turbo is not substanial. Only once you want to go beyond the rating of the turbo will you see the upgraded turbo realise all the benefits I have discussed above.

If you want to improve the boost vs kW ratio then your better off at looking at where you are loosing efficiency (ie pressure drops thru the inlet/manifold piping, etc). So if the turbo is pumping out 16psi and you lose 2 psi thru the inlet/intercooler, etc, then the engine actually only gets 14psi. So if you can improve the turbo to inlet restriction by say 2 psi (down), then the turbo actually only needs to produce 14psi to get 14 psi to the engine. As boost is proportional to outlet temp, the resultant reduction in inlet temp will realise other gains. This is why in general the Nizpro/aftermarket plenum/piping cars tend to make more power at lower boost levels than stock inlet/manifold cars.

Hope that helps.

Cheers

Robin.

[F6 UTE]

I have it on good advice by one of Australia's leading tuners that too much mid range boost accompanied with detonation and/or lean mixtures is the #1 cause of XR6T engine failures.

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Fantastic. But you ( cars ) aren't going to go as fast as possible for mods done. Irrespective of power output, unless you run a hard tune for DRAG RACING. Day to day, I agree, and I run 20% less boost and 20% less timing day to day.

Speed has a price.

[RAP1D]

See this is what I love about turbo cars, all the different posibilities for power and how it comes on but all the while wondering how close you are to breaking it lol.

I'm on my 7th turbo car over 12 years and have broken most of them in one way or the other, so it leads me to be alittle anal about this fifty kay car, I'd just like to find some good alternatives to running high boost.

I know what your saying there xlnt6, Ive agonized over compressor maps and picked micheals brain at gcg way too much over the years, but I see this gcg upgrade as a good way to achive 300 on lower boost, and from personal experience in upsizing turbos it looks like boost may come on at similar rpm, but hit max psi later, though more air per psi all over the rpm range. Perhaps giving us an easier on the rods 300wkws....

As for comp maps, has anyone ever seen a comp map for the stock ford/garett turbo?

We've all seen plenty of maps for various build GT40s and GT 35/40s... but a map for the accual ford turbo?