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Big Turbo on L6 ?


clear2me

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Those are not "Big", and depending on your altitude the GT42 may indeed be a requirement to get necessary airflow.

 

Frankly, the GT35R runs out of air around 650hp and it's frustrating as hell to have spent that kind of money only to find out, in fact it's too SMALL!

 

The "X" variant should be marginally acceptable (I hope!)

 

See above referenced page regarding GT35 fitment.

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Hello

 

Thank you for all reply

I am very shy cos my english not very will

 

My piston is JE 88.5mm

The crank 88mm strock

The head is P90 46/38 full port

compression is 8 to 1

 

Cos my english not very will so i neec help to find

The best turbo before i buy

 

Thank you

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Mohammad - I run a GTX35r on a L2.9. It has virtually no lag. At 2.5 pressure ratio it develops approximately 10% more lb/min than the GT35r. 10% is quite a bit when you consider the key to hp with a turbo is air flow (not psi). It packages well. No issues with enough space. It's considered a medium frame. As Tony said, it is not a big turbo.  My 2.9 will soon become a stroker. My target hp is 600. The GTX is a great turbo for my application.  

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At 2.5 pressure ratio it develops approximately 10% more lb/min than the GT35r. 10% is quite a bit when you consider the key to hp with a turbo is air flow (not psi).

^^^ Fat old white dude leans back and smiles, thinking "someone got it, maybe there is hope for the world yet!"^^^

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Hi Tim

 

That looking great

So i order Gtx42 ?

What the good housing size ?

What good wasgate ? And blow off ?

 

Thank you

Okay, let's step back for a moment here...

The GT42 is a _really_ tight fit - you will have to custom fabricate an exhaust manifold to be able to get it to package (this is probably the same for the GT35 - I know TimO is using a custom manifold, and I'll let Tony confirm for jeffp's car).  I don't think that there are any exhaust manifolds available currently that won't require modification for a turbo this big - it's not going to be a matter of just bolting something on.  Also, I had to modify the compressor outlet to get it pointing in the right direction in the engine bay without adding undue restriction - here's a pick of the mockup:

Engine_090.jpg

wilma3.jpg

 

Next the GT42 is going to require a 4" exhaust, which is not easy to package, either.  

Assuming that you can actually use the airflow this turbo creates, the resulting power will almost certainly destroy the stock drivetrain.  Do you have a plan for the transmission and clutch, for instance?  Brakes/suspension/tires? Fuel delivery?  This is going to require a LOT more fuel than a Walbro or the stock tank can deliver...

 

It's entirely possible that you are already prepared for all the other stuff that need to be in place _before_ you start thinking about a GT42, but I can't tell from your posts so far.  I just want to make sure that you understand what you are getting yourself into...

Edited by TimZ
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Hi

 

TimO thank you for reply

Any more info and photos for exhaust manifolds ?

 

TimZ thank you for great info

Yes i will work on all car parts

 

Now i will install z32 tranmision with ORC twin clutch plate and i will order All shaft from Driveshaft shop

 

Now i am working on engine and turbo size and WG and blow off

 

After that i will work on tire brake and all

 

I think twin Bosch 044 fuel pump will work fine

 

Thank you

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Hi

 

TimO thank you for reply

Any more info and photos for exhaust manifolds ?

 

TimZ thank you for great info

Yes i will work on all car parts

 

Now i will install z32 tranmision with ORC twin clutch plate and i will order All shaft from Driveshaft shop

 

Now i am working on engine and turbo size and WG and blow off

 

After that i will work on tire brake and all

 

I think twin Bosch 044 fuel pump will work fine

 

Thank you

Twin 044s will be just enough, probably if you don't plan on running ethanol (E85 for instance).  You'll need about 50% more than that for E85.  I would recommend paying attention to the fuel tank's flow capability - while you _might_ be able to get enough flow out of the stock tank, the resulting restriction is very likely to cause cavitation at the pump inlets, especially during hot weather (you are in Kuwait, right?)

 

So, to answer your question a few posts back, if you want something pretty big, the GTX42 would be a good choice.  I'm using the 94mm inducer (GT4294R), with a 1.00AR T4 turbine housing, and I think that this is the smallest one available (!).  This combo results in a pretty much 1:1 intake to exhaust manifold pressure ratio which is helpful for selecting a cam for high rpm flow.  However, it does not make full boost until ~5000 to 5500rpm.  I have fabbed (with help from James Thagard - do a search on "spoolie jobbie") a device that throttles one of the two scrolls in the exhaust turbine to effectively halve the AR at low rpm and make it spool faster, but that only makes max boost start ~500rpm earlier.  On the bright side, it does start building boost at around 3000 rpm, but 28psi doesn't happen until ~5000.   Here's a pretty good graph showing RPM, intake manifold pressure (MAP), and Exhaust manifold pressure (EBP):

dyno+ebp.jpg

 

I'm using a 60mm HKS wastegate with an EVC IV boost controller, and that's been working for me.  I don't think I'd want to run much smaller than that.  

 

I'm running a older HKS BOV that I don't think is available any more.  I've also ported it and enlarged the valve size on it.  Many of the BOVs currently availabe are undersized in an effort to make them louder - for performance it's a better idea to get one that will flow more and let the sound take care of itself.  There is a thread that discusses this here.

Edited by TimZ
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The GT35R JeffP is running is on a Euro Manifold, with the standard spacer. Most of the information is on his Anglefire Site. The Spool he gets is at 3200 like clockwork, but falls flat at 17psi around 7200, and around 6800 at 21 or 25psi. Meaning his engine is stonewalling the GT35R. He hopes the New X will solve that issue... I have sent on TimZ's last dyno sheet showing that 7,800 rpm power peak as a 'told you!' to show he should have made that run at 8psi right off the bat like I suggested to be able to know where his cam peaked. 

 

The car makes 2-3psi boost WOT almost anywhere below the 3,200, and then goes balls on at that point to whatever he's set the controller to--anywhere from 17-25 we've done runs...it just flattens out on the top end because the turbo runs out of airflow.

 

He had the SFP header...and junked it for the documented reasons you can find elswhere at this site. The revelation to him that the Nissan manifolds were cast steel and not iron, and could be welded got him to grinding the mating area to port-match his exhaust in the head, and then mount the turbo on a cast iron manifold with a pipe welded into it for a TIAL wastegate (he goes into specifics on what size on his website...something about a 42mm flowing less than the 35mm because of the design application.)

 

So it appears the useable rpm range is 3,200-7XXX on the GT35R on JeffP's setup. The hope is that the GT35X will allow those 17psi runs to 7,800 or so... The cam itself does not 'come on' until 3,500 and at 4,500 the torque is massive. Third gear in the ZXT is running 70mph at 3,250, and when you go WOT the boost is instant. If you can hook, there's a little Quaife Compensation as it will torque steer you from the back one lane or the other and you have to counteract that to keep going straight and in 3.7 seconds you're passing California Impound and Incarceration speeds in time to shift into fourth and ask the lord for clear lanes and no swervers!

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TimZ thank you very mush for great info

 

I need all help for every one ;)

 

Tony my english not very will So i cant understand you 100% ;)

 

Do you means L28 engine not work on Gtx42 turbo ? Or not work on high boost like RB and 2J engine ?

 

Thank you

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Either will work.

The GT35R or X is a smaller Turbo, and will spool quite a bit earlier due to the availability of both 0.63 and 0.82 A/R Turbine Housings.

Really, it's where you want to run the car, some people will want boost (hard boost) delayed until a higher rpm/speed to control traction, and then pull to a higher rpm for higher top speed.

 

The GT35X hopefully will allow the engine to make full boost from 3,200 to 8,000 with enough air . . . Jeff will have to determine where his Power Peak Occurs (as Tony Echoes again 'make a run at 8psi to see where your peak happens...) and then determine what boost the turbo will end up making for peak efficiency and power at that power peak. It may make 25psi all the way to 7,800...which would make Jeff happy. Maybe only 17psi.... 

 

Obviously the GT42X works on an L28, as TimZ is doing it as well. 

 

It all depends on your horsepower goals and where you want your power to be. For a street car having power available at 3,200 is very nice.

 

Incidentally, JeffP formerly had a TO4 on that engine which came on hard at 3,000. Problem was it was like a switch, the engine went from 150HP at 2800, to 450HP at 3000. It was hard to control.

 

Now, on a smaller displacement engine (L28, instead of a 3.0 liter) the  engine with better porting and cam is making much more horsepower BEFORE hard boost comes on, and is far more controlable. Much to Jeff's chagrin, he is making more horsepower and torque on a bone-stock L28ET bottom end and all his bolt-ons at 17psi than when he had his car featured in the magazine at 28psi and 6,800 rpmps (475 vs 450rwhp)

 

The 3.0 makes even more, but due to the GT35R being slightly low in flow capability, tops out above 600hp. The GT35X should either bump that by 100, or at the least allow the car to pull cleanly at some boost level all the way to it's power peak which should be around 7,800 rpms.

 

It will be at that point that Jeff will curse me for suggesting he should buy a GT42X because he now lives 'at altitude' in Reno Nevada, has cooler air, lower density, and needs the additional flow the GT42 Compressor provides. 

 

Thing is, Jeff is STILL running a 3" exhaust on a fully equipped S130, so it all fits and can be fitted to ANY S130 Car out there in similar fashion. His goal was to prototype a solution for an HONEST 500HP setup anybody could replicate. He's done that, but isn't finished because now it's a 600HP system.

 

If you haven't looked yet, his "Extreme 280ZXT" website at Angelfire has a lot of photos to show what he's done to make parts for the car, and to fit the larger turbos to the engine bay.

 

PERSONALLY, I think High-Boost may be out of the question for your 3.2. It's a thin wall you have there in the cylinders, and if the block wasn't sonic tested before boring, you may be courting disaster if you detonate with a metal head gasket. This was common in Japan ages ago. Generally, high boost turbos are best used on thick cylinder walls. Usually nothing more than 3.0 liter strokers for best longevity. 

 

A lower boost turbo on a 3.2 will still make prodigious power, with less chance of "going boom"--but you won't necessarily NEED a GT42 to do that flow. As TimZ states, depending on your chassis, a 125mm exhaust pipe from the engine back can be an issue for packaging!

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Remember, it's not BOOST that makes horsepower, it's FLOW.

 

Both TimZ and I are discussing compressor sizing for providing sufficient Pounds-Per-Hour to accomplish a set equation for production of fuel combustion at a specific Brake Specific Fuel Consumption rate...  How much horsepower you want determines how much fuel you need, and how much fuel you have determines how much air you want.

 

But properly porting the head, running the right cam, etc, as JeffP has demonstrated, it is possible to produce MORE horsepower at LOWER boost than a previous iteration on the same or even smaller engine! 

 

Get the air into the engine efficiently and "boost" is not necessarily required. The 2-3 psi at WOT before threshold on Jeff's car makes the engine pull like a much larger displacement due to aid in pumping efficiency. 

 

"Boost is merely a reflection of resistance to flow." I do not ascribe to the Corky Bell 'throw boost at it' school of Turbocharger Application. Properly build the engine as you would for an N/A and you will be rewarded with the same high-rpm surge and rush of power as the original N/A and not something like a big-block Corvette. I've been in Z31's that were boosted to 600+ HP and they were like big block Corvettes (or maybe a Chevelle, something big) with a shift point at maybe 6,300...or worse a power peak at 5,500 or 5,800. 

 

I much prefer that rush to redline that pulls hard from onset of boost to 7,500+... and to get there, you have to flow! Once you flow properly, you can tolerate a MUCH larger compressor on the engine than you normally ever would. Search here for "Big Phil" and his L-Series GT35R application issues. Mismatched and took a lot of sorting to work out. 

 

I'm saying the engine is a package...you just don't buy the parts and have them assembled. What are your power goals and how do you want the power to come on? THAT will determine what turbo you want to use more than anything else.

 

Cheers!

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For reference, I hope to be prepared to saturate 1400cc or larger injectors with ethanol... I'm going with THREE medium sized pumps. Why three? Redundancy. If one fails I can still make it home and maybe even keep from blowing a motor if it happens without me realizing. Also, one over worked pump tends to transfer more heat into the fuel than two smaller ones under less individual load flowing the same overall amount.

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For reference, I hope to be prepared to saturate 1400cc or larger injectors with ethanol... I'm going with THREE medium sized pumps. Why three? Redundancy. If one fails I can still make it home and maybe even keep from blowing a motor if it happens without me realizing. Also, one over worked pump tends to transfer more heat into the fuel than two smaller ones under less individual load flowing the same overall amount.

 

1400cc? You planning on making north of 700hp? :shock:

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E85 requires sizing for fully 50% more fuel than gas, and you size for flywheel not at the wheels.  Does 700 at the flywheel sound impossible to you?

 

No, I don't think 700hp is "impossible". I was merely exclaiming at Nathan's goals...

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