When do you need to move to forged pistons and steel rods??

I have been working and new plan after v1 of my plan to prove that 8vs are cool fell flat!!

So as above really.

so im looking at a NA again, I am tempted to build a boosted engine, but not yet.

 

Still sticking with 8v?...

 

8v's are cool

 

Yup agree...

The GTI has Cool performance with an 8v motor... Pretty much like' blue motion' but then real 'R' Hot GTIs tend to some sort of device 'Fury' fitted....Some say...lol

 

Of course it's 8v!!!

I want circa 190 hp

 

13:1 compression and a gs6 cam...

 

And how much torques?

 

mr hillclimber is the man for 8v power (jmr)

 

Right serious head on! Depends on what you want to do and the level of tune.

A 2.0 ltr 8v with 190bhp isn't going to be top race spec so unless it's circuit racing I wouldn't think it would need steel rods as it's not going to need to rev as high as a 16v for the same level of performance. It will need to be running big compression though as it will need quite a lot of cam so I'd imagine forged pistons would be a must.

I'd go for std rods and ARP bolts myself. I've run that spec up to 9000rpm with no problems.

Money needs to be spent on head work, management and cam/valve train - Being 8v only 1 cam and 8 of everthing else so half the cost of a 16v

Second hand 45mm throttle bodies of some description (plenty out there) will do the job and a decent off the shelf exhaust manifold/system (suitably modified before fitting) will also do.

The trick is plan properly. A cam that will give you 220bhp will cost the same as a cam that will give you 160bhp so make sure you buy the right bit in the first place! Pistons/cams/valves/headwork are the most important. Every thing else is dictated by these.

 

Wacky cams can need wacky gear ratios, something to bear in mind. I sold my lovely gsxr1100 to buy a proper set of 020 ratios etc so I could keep my rallycross golf 8v singing near twenty years ago.

BTW what are going to use this mega bhp engine for? (out of interest)

Jon

 

It's interesting John that the long stroke 2.0ltr seems to be much more torquey (or has more drivability) that the shorter stroke 1.8ltr engines. The 1800/1900 engines I've seen running seem more revy and seem to need better ratios (not that you'd realise mine was less revy sitting in the car!). I also think modern electronics also disguise so much. Whilst the out right power levels are probably not much different I'd wager the drivability is much better. You could drive mine down to Tesco and potter around town no problem.

I ran an early FM 1600 gti box on mine with a 4.47 FD and the ratios were fine, and mine has quite a lairy cam in it. I don't think they would have been so good on an 1800 though from what I can tell.

Mind you rallycross is another thing of course.

 

FM/FD 020 box is the one of (std) choice. My RXer was in the 1600 class and had a 2000rpm powerband. Clockwork ignition and carbs..

 

Interesting stuff chaps,

Jon as for its use, stupid as it may seem, it's not for competition purposes, it's more to prove what can be done.

Tony I were you running STD rods in a 2.0?

I'm a bit undecided on the bottom end, a 2.0 means I could use 159mm rod with some off the shelf pistons, or I use the bottom end I have with the diesel crank 159 rods and custom pistons.

I have an ABA head to use at the top

 

I have the throttles similar to yours Tony, and I have some dodgy looking flanges to adapt them to fit the xflow head.

 

MTS Motorsport do an inlet manifold to suit the crossflow head that will take itb's/carbs.

 

Alan,
Forgetting cost and the practicality of the project,

If 190bhp is the goal, you would need to rev the motor significantly more than stock for sure so H section rods will be required.
You will need high compression and pistons that can withstand high levels of cylinder pressure. So that means uprated pistons which will be forged units.

I would suggested 2.0 litres with the longer rod as there would be more dwell time at TDC for expansion and less friction. This would be important at high revs.

Application should dictate why you want to do this but it is just to prove a point?

 

Just bought a 2L X flow and in the middle of stripping it to see what possibilities it has. Once in bits and examined it may be for sale, if its any use to you.
Back to gear ratios.
A measure of how useful the set you are going to use is. Take 3rd gear as an example. Find the revs the cam comes on song. (full race 4000-8000 range typical) and work out how many mph this equates to. (inc tyre rolling diameter etc)T hen do the same for max revs. It may open your eyes aas to how 'useable' the end result of you efforts will be....
Just a thought, and why Ive just fitted a 4.8 FD into an 020
Jon

 

There are lots of gear calclators available and as you say Jon/Alan and it is interesting. For competion (sprints/hill climbs etc) you have to ignore first I reckon and just base it all on 2nd to 5th. I spent two season not using 1st other than for driving round the paddock, Sometimes hairpins and certain corners didn't quite have the right gear but other wise fine. COmpomise between top speed and getting second gear low enough to use. Never found it a problem with a 4.47, plenty of power to get off the line.

There are a few decent final drive ratios available for the 020 - 4.25/4.47/4.8, all for sensible money. MTS list a few.

That said I've not gone quicker anywhere yet with a proper VWMS gear kit with all 5 gears I don't think that's the cars fault though! Maybe I should try a 4.8.

Agree with Toyotec on the long rod but don't think steel rods are a necessity, VW rods are strong. The bolts are the weak link, just fit ARP's. I actually have a set of 159mm steel rods sitting here but I've never bothered fitted them, I just don't think the VW rods are weak. That said, as Toyotec says, if money is no object then for peace of mind you might as well fit a set.

The F3 throttle bodies are nicely made. The problem I had was inlet tract length, shortening it enough to suit the revs, as F3 engines don't rev that high. Still not idea but used very short radius flanges then machined them down some more. Seems to work much better now. Be careful you don't lengthen them any more than they are std! Maybe even machimning the flanges down to gain 5mm here and there.

 

Agree stock rods are good. I also have a set of steel rods sitting there, unused.
Back to gearing (again)
I guess Alan's car will be a road/track based vehicle. The point I was hinting at is nothing spoils a cammed car's driveability more than having it hopelessly overgeared. Take the F2Stu cordoba. 142mph at 8100rpm in 4th on the rolling road.
Jon

 

In Stu's defence, this was a road/trackday car, not a race car. Pukka race gearing drives you nuts on the road - thats ultimately what persuaded me to stop driving mine to events.