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Author Topic: 8v engines: how quaint  (Read 382 times)

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Offline RobT

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8v engines: how quaint
« on: July 13, 2012, 03:55:30 pm »
When 16v heads are available, why waste all that time and effort on 8v heads?

 ;D

What am i missing?

2008 Audi A6 2.0TDI S-Line
2004 Audi A4 Avant 1.8T Quattro S-Line
1996 Seat Ibiza 16V F1.5 Race car

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Offline Stooza

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Re: 8v engines: how quaint
« Reply #1 on: July 13, 2012, 04:22:46 pm »
I guess it's down to what you like. I have 8v and 16v and they both reward me in different ways matey. There is just something about an 8v that breaths at the top end tho..
Mk2 2.0 16v GTi (built for track day fun)
Mk3 16v GTi (standard)
1970 1915cc type 1 beetle (rebuild on hold)

Offline JMR

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Re: 8v engines: how quaint
« Reply #2 on: July 13, 2012, 09:22:01 pm »
Now now...this is'nt the fight club...lol! :D

Quite a lot comes into it as we all know...class regs...costs. ..performance requirments.

A friend of mine has both an 8v Mk2 GTi and a Civic type-r. When asked if the Mk2 ever feels lacking after getting out of the Honda his answer was "does it f$#k"!

The Mk2 isn't "quite" std...2tr, ported head, lumpy cam...circa 150hp...but as he says. .it "grunts" better low & mid range than the Honda. .the Civic picks up where the Golf tails off in the rev band..."I don't always want the drive like my pants are on fire" was his statement. ."which the Honda needs to get the key advantage from it".

Offline RobT

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Re: 8v engines: how quaint
« Reply #3 on: July 13, 2012, 10:01:16 pm »
Just being provocative....:)

Of course a lot of factors come into it.
2008 Audi A6 2.0TDI S-Line
2004 Audi A4 Avant 1.8T Quattro S-Line
1996 Seat Ibiza 16V F1.5 Race car

Offline Tav

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Re: 8v engines: how quaint
« Reply #4 on: August 18, 2012, 12:16:19 am »
Class regs for me otherwise I'd slap a 16v head on the 8v Polo block...

...but there is something intriguing about the challenge of getting an 8v to perform. 

Offline Tonyb

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Re: 8v engines: how quaint
« Reply #5 on: August 18, 2012, 03:22:27 pm »
Don't get sucked in to the 'you need a 16v head to win' myth! There is no doubt that a 16 v engine will out perform an 8v engine, like for like, but there are 8 more of everything required so there is a cost to consider as well. The difference is not as great as everyone would have you belive, trust me I know  ;) just doesn't sound very trick.

This is how I see it (although I'm sure everyone won't see it the same). Based on cost/work involved etc. Obviously it depends on what you start with 8v or 16v. If you want up to 160bhp either use a std 16v with some sort of induction/ECU mods etc or tune an 8v cams/head/pistons/induction. Probably cheaper if you start with a 16v but not if you have to source a 16v.

If you want between 160bhp to 200bhp probably 16v only, cams/porting/induction. There is a big jump from 160bhp to 200bhp in an 8v but it doesn't need to cost much more than 160bhp if you miss the intermediate stage out. So over 180bhp up to around 220bhp 8v is probably more cost effective as you have 8 of everything as opposed to 16 of everything, over that your back in to 16v territory.

200+bhp 8v Golf is a seriously quick motorcar and with a good chassis and a tidy driver is good enough to beat most 16v cars you are likely to come across in the class on a good day. The cam/pistons/induction etc to achieve 160bhp as opposed to 200bhp in an 8v cost the same, you just need to spec the right one for your needs! You need more head works/valves/valvetrain work etc for higher power engines just because the parameters are greater and the stresses bigger.

In summary plan and understand what you want to achieve before you start and buy everything once as opposed to buying something and 6 months later buying a bigger/lumpier/wider one! As I said 8v doesn't sound trick and ultimately a 16v will go quicker but don't believe everything you hear about 8v's  ;)

Offline JMR

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Re: 8v engines: how quaint
« Reply #6 on: August 30, 2012, 09:24:25 pm »
Well said Mr b!....

Particularly the bit about planning ahead regarding the use an engine is going to be put too...numbers arnt the be all and end all...performance, and the delivery of that performance/power spead should be taken into account.

Offline Stooza

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Re: 8v engines: how quaint
« Reply #7 on: August 31, 2012, 11:59:57 am »
Yeah, I will be owning both 8v and 16v soon, I cant give up on the 8v, it's addictive and rewarding
Mk2 2.0 16v GTi (built for track day fun)
Mk3 16v GTi (standard)
1970 1915cc type 1 beetle (rebuild on hold)

Offline chrismc

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Re: 8v engines: how quaint
« Reply #8 on: November 10, 2012, 01:35:43 pm »
I have owned both stock & mildly modified versions of both engines in 8v & 16v form for fast road/trackday use.

In stock form the 1800 8v always feels more tractable & torquey- despite lacking that ultimate 16v top end fizz

Add a 2L block & some fruity headwork & you have a punchy 16v beater even on stock injection.

I only went to a 16v as it was a better budget trackday engine out of the box. A good kjet 2L 16v gives that torquey 8v feeling low down, but keeps revving up top!

I do wonder what my 8v would have been like with some more compression, x-flow head & ITB's

There was a guy on cgti who spent 's on such a setup but it never fulfilled its potential. Think he ended up going VR6 :-\








1995 BB1 Honda Prelude 2.2 VTEC track hack
206BHP/153lbs/ft

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Offline Tim Moll

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Re: 8v engines: how quaint
« Reply #9 on: November 10, 2012, 02:31:37 pm »
The engine that'll be going in my next project Mk1 is a 2ltr with forged Wiseco pistons, custom machined by JMR, forged rods, lightened, knifedged and balanced Hotgolf crank.  Block has been decked as well to get correct piston protrusion. On top will be sitting a JMR X-flow head, based on a US spec OBD1 2ltr head, fitted with Supertech 40mm inlets and 33mm exhaust valves, matching uprated dual spring set, titanium caps and solid follower conversion.  Cam is yet to be decided....I have a Kent GS6 (well actually it is sitting down at Jason's along with everything else...lol) but Jason and I are thinking we may go for a custom JMR profile cam instead  ;)

Induction will be via Jenvey 45 ITBs on a custom JMR inlet manifold, haven't decided what we are doing for an exhaust manifold yet....maybe recruiting a heavily modified Ashley jobbie....if I can prize it out of Tony B's hands lol.  Management is via a Emerald K3 ecu with custom built loom.

If we don't hit 200bhp out of that setup then next step will be changing the head for the other one Jason will be doing for me....another of the same but this time full race with 42mm inlets and 35mm exhausts  ;D
« Last Edit: November 11, 2012, 10:11:33 pm by Tim Moll »

Offline Tonyb

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Re: 8v engines: how quaint
« Reply #10 on: November 17, 2012, 08:20:28 pm »
Sounds like it should be a good one Tim. be interesting to see how it performs. I't should make some good power.

As Jason says they can take a lot of cam as long as you have enough compression use as much as you can. Modern electronics can make them run like **** cats even with lots of overlap.

You could happily drive mine down the shops even with 320 degree duration.

You can have the manifold if you want it. I'm a hoarder but it's not doing anything at the moment and it won't fit my car anymore so no better time to pries it off me! and it's proven to work fine.

 

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