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

I can't explain Eddie, it's something I need to do, I know 16v, VR6 or even 20vt would be easier for bigger numbers and probably less effort.

 

Ok...

 

Do what makes you happy (And if you don't like what you have created, you can always change it).
I remember when you started designing a plenum and it was really interesting reading, I was always looking forward to your updates. This is equally as interesting, a project which has been stewed over in my mind many times, X flow 8v, ITBs, big compression, hmmm.

 

Looking forward to this build also, and the discussion.
That was no critiscism of the F2Stu car or Stu. Just an observation. He wholeheartedly agreed on the gearing, it was budget reasons it wasn't addressed by him.
Jon

 

Maybe we should should start the NA appreciation society. ATMO ATMO ATMO!

-NAAS- has a ring to it! lol

 

What you want is a sound file of Brookster saying NASP!! lol

 

lol

Where is he?

 

Still around on FB.

 

I miss his green Mk1 and forum presence, shame he is not on here much.

 

NASP

The MK1 is coming out of retirement at VW Action @ Santa Pod in 2 weeks

been working on it today Cage being fitted this month too

 

And Jacamo for XXXL race suit! lol

 

Sorry mate

 

In answer to the title Alan....

Std rods are good to 8k in shorter bursts like hillclimb and sprint use, if using over 8000 for longer periods like circuit racing or rallying / rallycross id go with steel rods.

Cast piston use varies....im running circuit engines clipping 8k with no issues so far but with only just over 11:1 c.r and 160hp. Slick 50 spec engines making similar power but with less revs will eventually break ring lands on just short of 12:1 but with heavily decked crowns. Id be comfortable using decent cast pistons unmodded to 7500 in short bursts with 11.5:1 and around 170-175hp...after that it's a gamble.

To make the circa 190 yr after you'll need around a 310 cam...poss a little less, 12:1 & 7-7,500 minimum...id only run forged pistons at that level.

The thing is...do you really need 190hp?....we have circuit race 1800 8v holding its own with 162hp against 200+hp 1.8t's and more on std crank/rods/pistons.

Id poss consider a sub 170hp on a budget build with lots of grunt.

 

Are these engines in race-spec mk1s though Jason?

Alan has a road car mk2. It's his car at the end of the day and he does as he pleases but a peaky 8v engine isn't ideal for his application really. (all imo!)

The previous posts about suitable gearing for this engine spec can't be ignored either.

I remember on my 16v I had Schrick 268/276 cams with a mk3 8v 'box (DFQ,longest 020 ratios) it was crap in a nutshell, no quicker point to point than with the twin exhaust cams it had previously, rubbish at 30mph trying to go through speed limits. I think they lasted 2 weeks before I sold them.

 

I agree. Thing is Alan says he wants to show what the 8v engine could do. So it is a bit difficult to start a shopping list not knowing the real application i.e. as Jason was stating or road use to ferry family or drag racer etc.
I suspect for an 8v it will be quite elaborate if it is to achieve that type of '190bhps' I tend to see at GS. I do not get it but its Alan's project so I watch on.

 

I did post something on here earlier ref xflow mk2s but deleted it as it was a bit of 'willy waving' really.

But anyway.. lol

When I lived at Worcester a local guy with a mk2 who has a bad 8v fetish was talking about a 'race-spec' 8v x flow bla bla. At the time I had the mk2 VR6 on the road and took him out for a run in it, he said it went well but an engine conversion was 'cheating' lol

He was going to prove how to get power from an 8v!! Anyway, I'm not sure on the base engine spec but it had twin 45s on at first big cam etc.
He had it set up for drag racing (jacked up solid rear suspension,drag radials at 8psi and all that) I had a few runs against him at the pod (I was in the road tyres I'd driven there on) , I 'won' all the runs.

He's since gone Jenvey ITBs and some sort of stand alone ECU (poss Omex) but still his runs aren't all that for the and effort.

Sounds good though, I'll give him that.

 

It is indeed Gary yes....898kg's inc driver on a 3.9 f/d...so lighter than a road weight mk2, but not especially low geared.

Id guess Alan wants to create a really powerful road spec mk2 with a nod toward performance rather than every day road use...hence my thinking of a grunty 170hp lesser spec engine.

The closest I've done recently in a mk2 is a std valve head & 280 cam on 45 dellortos...with 150hp that pulls the mk2's stripped 870kilos up a hill fairly lively, tho on a 4.25 f/d to be fair.

All the full on 1800's making 190hp are still totally drivable on either carbs or itb's, but on 4.25-4.7 f/d's.

In a road weight mk2 at around 920 kilos with a 2ltr version of a de-tuned hillclimb engine at around 180hp on a 3.9 f/d, it would make a lively package.

Tonyb's 2ltr still has bags of mid range grunt with over 220hp, so they're not all top endy even with a 320 degree cam.

We had a stripped but road going mk1 in recently...steel panels but perspex windows, drivers seat & dash, weighs 700kgs, running a mild road 1900 8v on 45's, 270 cam, 3.9 f/d...ran a 14.3 1/4 at the pod a couple weeks ago with 140hp (at the flywheel) and road tyres....nothing special, just delivers it well.

 

Thats must be Ross your on about

 

I think an 020 on a 3.89:1 is as low as you'd want on a road car (depends how much you use it and how far you go I suppose!)

I had that in my last 020 box on 16v and had a mk2 8v 5th as was doing a lot of miles on road as well as track days at the time.

As Rob said previously, 'race-spec' gearing would do your nut in on the road for anything more than an occasional blast out.

 

Brooky, yes!