Gearbox + Flywheel Help!

[GrahamHDi]

I am wondering if the dturbo gearboxes go on the hdi as a believe they rev to 6.5? Also whats a good flywheel to use i was going to use gti6 as it is noticeably lighter but dont have exact weight deferences, also this is all for stage 3, will be running td04, r70, 1800fps and so on

[Danny2009]

It's not the box that makes it rev high .....

[GrahamHDi]

I was just under the asumtion that a drurbo box would help

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People tell me that many different things, thats why i finally joined here lol! Get some correct answers for a change

[Poodle]

Have a read of some of the recent threads in this section, theres been a lot of speculation as to the value of the 1800bar frps. Id avoid lightening your flywheel too, it seems to have caused issues on other builds. Otherwise your list looks pretty spot on, excusing the dt box lol.

[GrahamHDi]

So no need to lighten fly or change the box, ive had a look at some threads, seen a 6 fly and dturbo clutch but adont thing there running 300+ftlb, thanks for the input
Im under the impresion from pro steve i cannot go any higher than stage 2 with out the fps

[Poodle]

You can't go higher than stage 2 without putting more fuel in, until recently it was assumed the easiest way to achieve this is to raise fuel pressure. There are several schools of thought on the matter, but i'd suggest doing some research and deciding for yourself which way to go.

[GrahamHDi]

Thanks mate

[pro_steve]

Fuel pressure is important for heavy stage 2 / stage 3 tunes for a simple reason. There aren't any good injectors which can flow more, the only way to flow more fuel through the same size injector holes (before the exhaust stroke) is to increase the pressure of the fuel. If you know how to do this without tripping the cut out conditions then it's not that hard to do. Obviously its easier to do this with a good fuel pump.

The theory is all there, and this has been confirmed several times by TB206 who has pushed the HDI engines the furthest out of everyone. I've also found it to be very beneficial on the heavier tunes, assuming the fuel pump is good. When the pump cannot meet the demand it's kind of pointless asking for it and just creates extra resistance for not much benefit.

It's not too hard to work out when injection will end based on the start time, engine speed, fuel pressure and the injector calibration time. With this it's clear that end of injection is far too late when compared to stock values. Yes, you can push it quite a bit later, but this results in high EGTs as your fuel is burning as it goes through the turbo on the exhaust stroke.

With the bigger turbos this isn't so much an issue as it is when pushing the stock turbo hard, the bigger turbos seem to provide enough air to burn most of the fuel cleanly, if you want to push it really far you need more fuel pressure otherwise you'll have smoke. Burning the fuel in the cylinders rather than the exhaust also gives the benefits of reduced exhaust manifold pressure and temperature.

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And Graham, you don't want to rev much past 5 on the HDI, you'll just end up with a con rod shooting through the side, it's just not designed to rev that high! I thought you need reliability still? lol

[GrahamHDi]

Yeh mate i do want reliability am just trying to make it as fast as possibly can lol but yes your right, there is a fine line between reliability and being evil!

[Piggy]

why would you need to rev to 6.5k?!

Better setup, a MUCH better turbo and stick with the hdi box and fly.

[GrahamHDi]

Ive been strugling with turbo for a while i didnt know what turbo to buy and got that for £40! And whats a better setup than i have?