Gearbox for 172 TURBO

[ripp]

We have here a turbo 172, problem is the original gearbox needs an upgrade or find another one capable of taking 400+bhp and massive torque.

car presented here:
http://www.cliosport.net/forum/show...-Sport-99BFF&p=7173011&highlight=#post7173011

The owner took me last night to a spin and what can I say, on street rubber the first three gears you can't put that power down.. then a knocking noise appeared in the box and the fun was over
Any suggestions welcomed!

 

[T.Trophy]

You need to speak to Scoff or do some research on him. He fitted a VW gearbox onto the F4R after he destroyed a couple of JC5 gearbxes on the strip. It's not the easiest job in the world but it can/has been done.

 

[ripp]

thanks for the reply, pm sent to Scoff now
here's a recent graph that came out:
View attachment 46975

 

[T.Trophy]

367bhp and 339lb/ft pretty good, what boost you running it at?

 

[felixb]

these are whp, and I'm running 1,6 now...

 

[T.Trophy]

Think I might have to turn mine up from 1.2 and join you

What size injectors you running?

 

[felixb]

megane 480 cc injectors, and 4 bar of fuer rail pressure regulator taken from a leon 1,8T engine, I hope I nailed the technical terms "

 

[T.Trophy]

What duty cycle are you running the injectors at?

 

[felixb]

the guy who did the map should know, I'll ask him. I'm almost sure they're not at the max though

 

[sideways danny]

367bhp and 339lb/ft pretty good,

What size injectors you running?

the maths (rule of thumb) say they will do 307 at 80% and 384 at 100% at 3bar (flywheel) bumping pressure will give a little more headroom, but not a lot.

I'd say it was a little optomistic for wheel power, but it's a really impressive build none the less

 

[T.Trophy]

Just what I was thinking Danny, I've had a look through felix's photos and hes done a cracking job with the intercooler pipe work, no tight bends etc... I think @1.6 bar the power delivery is going to be pretty brutal unless he has a progresive boost controller, or the ECU has the same capability?

Danny, you bought any cams lately? I was literally in the process of getting his bank details

 

[sideways danny]

lol, might have done i'd been waiting for the details for 9 hours though. I did lol hard at the "can i have them next month" posts from some people

 

[ripp]

the car has Haltech stand alone, and over 4 bar of fuel rail pressure, the fuel regulator is set to open at 4 bar. if additional pressure comes through the vacuum hose from the turbo boost the regulator opens above 4 bar, thus holding above 4 bar pressure in the injectors=more fuel

 

[sideways danny]

=more fuel

not strictly true, not more fuel, just not less fuel due to manifold pressure holding it back. That's what the vacuum compensation on the regulator is for. Thats why injectors are a lot easier to max out on cars with a single fuel line and an in-tank regluator, no compensation, so the fuel pressure is effectively reduced by the total boost pressure
An increase in pressure doesn't give a huge increase in maximum flow. I think the rough rule is doubling the pressure will give you a 20% increase


Haltech standalone is excellent. I'm just sad they refuse to give any proper support to UK dealers, or give any warranty if you import them

 

[ripp]

 

[ripp]

the power output came about the same on three dynos, so it should be near the actual

 

[felixb]

the maths (rule of thumb) say they will do 307 at 80% and 384 at 100% at 3bar (flywheel) bumping pressure will give a little more headroom, but not a lot.

I'd say it was a little optomistic for wheel power, but it's a really impressive build none the less

Hi!
I'm the guy who did the Haltech install, mapping and some other things...
Here is a log from a 1.4bar pull:

I did not logged the duty cycle but you have the injection time and rpm, you can do the math yourself,take in account that injection mode is batched, 1-4 2-3....
The numbers that got out from this were 257.1 KW and 406.7 N-M at the front wheels.
Here is the result from the test with 1.7bar,so far I never heard anybody calling Mustang numbers very optimistic

 

[sideways danny]

boost control solenoid?

 

[sideways danny]

,so far I never heard anybody calling Mustang numbers very optimistic

I have!! that's what the americans use as a benchmark, and generally american ATW figures are regarded as being the same as UK/European ATF figures.

If that were what you have then it's a seriously powerful car and well done

 

[ripp]

boost control solenoid?

yep

 

[T.Trophy]

Danny is spot on with what he's saying.

On a single line fuel system as per a megane 225, where it has a 3 bar reg in the tank, when you up the boost to say 1 bar you will potentially only have fuel pressure in the region of 2 bar, as obviously boost@1bar+fuel@2bar will open a 3bar regulator.

In a twin line system the same as what I run, you have the regulator on the fuel rail, you also have the vacuum port on FPR so that what ever pressure is in the inlet manifold is also present on the same side as the spring. In this scenario you will always have the fuel coming through at whatever the spring pressure is, in your case 4 bar.

It's easy to assume that because you have boost@1.6 bar plumbed into the FPR port that 4bar+1.6bar=5.6 bar of fuel pressure, however in reality when the injector is open you will also have 1.6 bar of boost trying to push the fuel back into the tank which effectively cancels it back down to 4bar.

Hope that makes sense, obviously this is just the basic theory behind fuel injection in boosted applications.

480cc injectors running @ 4 bar will flow about 550cc, now if your running them at the recomended 80% duty cycle you'll only be flowing 440cc, even if you run them at 90% duty cycle, your still only at 495cc which to be honest is only a little bit more than what I'm running through mine? and your wheel figures are only a little bit less than my fly figures?

 

[felixb]

in reality when the injector is open you will also have 1.6 bar of boost trying to push the fuel back into the tank which effectively cancels it back down to 4bar.
Think again Boost pushing the fuel back through the injector...... What size has the injector outlet nozlle and what size has the injector fuel inlet???
I'm not sure what's the injectors flow rate,I just gave them a chance to see if they can flow enough or not. You have the logs and the AFR is fine.
About the Mustang numbers, I measured XXX stock cars, for FWD I multiply with 15% tranny loss, the wheel results multiplied with 1.15 gives very very close to the flywheel power .
Next week I will test a stock 172bhp clio and post the wheel numbers, this way will be able to tell an exact difference.

 

[sideways danny]

the size of the nozzle makes no difference. injecting into a pressurised vessel (the plenum) will reduce the injected pressure.

so 4 - 1.6 = 2.4

but then you add plenum pressure to the regulator, increasing your overall fuel pressure back to what you started with.

so 2.4 + 1.6 = 4

 

[felixb]

I have!! that's what the americans use as a benchmark, and generally american ATW figures are regarded as being the same as UK/European ATF figures.

That's not true, where had you read that?
At the wheel is at the wheel.... means the power that the wheel turns the dyno roller, the flywheel power minus the tranny plus the wheels and tire looses, the effective power that pushes you on the road .

 

[felixb]

the size of the nozzle makes no difference.

Ok, you ignore the hydraulics laws then.

 

[T.Trophy]

Don't take it the wrong way Felix, were just being inquisitive as both me and you are running very similar set ups, and consuming very similar amounts of fuel yet the results seem so far apart?

Did you find out what the injector duty cycle was?

 

[felixb]

In the log the pulse width at 6570 RPM is 11.725ms, this makes 65.95% duty cycle
http://www.stealth316.com/2-calc-idc.htm
The different results may come from the different VE of the engine.
The turbocharger is rated for 480hp http://www.turbobygarrett.com/turbobygarrett/catelog/Turbochargers/GT28/GT2876R_705330_2.htm

 

[sideways danny]

you're doing the calculation wrong. double that duty cycle

 

[ripp]

hey hey we're drifting!
car definitely is between the 380-400+ area, doesn't matter that much!
it needs a gearbox-fact!
shall we move the conversation in that area?

 

[felixb]

you're doing the calculation wrong. double that duty cycle

Input this numbers in the calculator 6570 RPM and 11.725ms, tell this guys why they are wrong ....
http://injector-rehab.com/kbse/idc.htm

 

[Fred@BTM]

how about a megane 225 block with the megane/nissan 6-speed ND0 gearbox

 

[ripp]

hard to find megane blocks around here (if not impossible) and they must be expensive also (combined with the gearbox). You can get them on e-bay I suppose but the price would be a problem. the VW gearbox option which Scoff adopted should be cheaper

 

[felixb]

hey hey we're drifting!
car definitely is between the 380-400+ area, doesn't matter that much!
it needs a gearbox-fact!
shall we move the conversation in that area?

Sorry, we were talking, not drifting
More exactlly 372.4 WHP
Felix opened the gearbox, it looks fine, just few signs of fatigue during the previous abuses. There is no gear broken or anything that comes from massive torque.

 

[Fred@BTM]

hard to find megane blocks around here (if not impossible) and they must be expensive also (combined with the gearbox). You can get them on e-bay I suppose but the price would be a problem. the VW gearbox option which Scoff adopted should be cheaper

well i have a block and a NEW box, you can have them both cheap if you can sort out the shipping side of things

 

[RSTuning]

On the F4RT engine with stock fuel pressure and injectors they will produce enough fuel for about 280hp at 11.8:1 afr @ 100%DC, they are not 480cc but little 380 (or so).....

 

[ripp]

what part number are the megane injectors?
tomorrow felix is gonna remove one and we'll compare the codes

 

[RSTuning]

8200511099 They should have a blue tag if they are the later ones.

 

[felixb]

Hi sorry for the delay, was busy lately so yesterday managed to get the injectors out. they have the same part no as above but done some research and they appear to be 480cc:
http://www.twingooc.com/showthread.php?4561-Uprated-Injectors-Thread

 

[RSTuning]

390's (or so)

480 would indeed offer much more room but the megane sport does not have them.

 

[Scoff]

Ok, you ignore the hydraulics laws then.

They are correct I'm afraid. You have to consider only the aperture at the end of the injector, or nozzle, whatever you want to call it. The pressure differential across that aperture and it's size is what is going to dictate flow. Sure, the fuel inlet is much bigger, but then the fuel rail is bigger still and ofcourse that makes no difference either.

Consider why a motor nealy always wants twice the injector duty at 100kpa as it does at 50kpa. It's because injector flow is a constant as long as the manifold:rail pressure is constant, and that's the job of the FPR.