4.2 induction kit?

[assynt road]

Hi chaps, read lots on here on 4.5 engine mods but has anybody done much to the 4.2? apart from turning it into a 4.5 that is! I was wondering if there is an induction kit made? I've already got a 'so called' sports exhaust, and have seen the ACT manifolds[ a bit pricey] anybody got any other ideas? Many thanks.

Assynt road.

[Markh]

assynt road said:

Hi chaps, read lots on here on 4.5 engine mods but has anybody done much to the 4.2? apart from turning it into a 4.5 that is! I was wondering if there is an induction kit made? I've already got a 'so called' sports exhaust, and have seen the ACT manifolds[ a bit pricey] anybody got any other ideas? Many thanks.

Assynt road.

Could be worth contacting Jamie at Castle Race Engines

[trackcar]

There's not a lot you can do on the 4.2 induction except the usual porting work. Ive just reworked a pair of manifolds for what will hopefully be a very powerful 4.2 engine. if it doesn't make a number with a 4 on the front I will be most upset so no pressure on the engine builder

[RichV6]

Joo,

This goes back to our converation at Croft. Keep us up to speed with this engine and your
new exhaust. I for one am very interested being more than happy to see what can be achieved
with the 4.2.

[clive f]

trackcar said:

There's not a lot you can do on the 4.2 induction except the usual porting work. Ive just reworked a pair of manifolds for what will hopefully be a very powerful 4.2 engine. if it doesn't make a number with a 4 on the front I will be most upset so no pressure on the engine builder

thanks mate

[trackcar]

sorry matey will keep you updated Rich

[AlVal]

wow, a lot of 4.2 owners ears are going to prick up if it can really be honed that well! I'm sure it's no mean feat though! keep us informed guys

[volospian]

trackcar said:

There's not a lot you can do on the 4.2 induction except the usual porting work. Ive just reworked a pair of manifolds for what will hopefully be a very powerful 4.2 engine. if it doesn't make a number with a 4 on the front I will be most upset so no pressure on the engine builder

Thing is, how much is it all going to cost to get those numbers? I can see it being not far off the cost of a 4.5 conversion.

[jammy_basturd]

trackcar said:

There's not a lot you can do on the 4.2 induction except the usual porting work. Ive just reworked a pair of manifolds for what will hopefully be a very powerful 4.2 engine. if it doesn't make a number with a 4 on the front I will be most upset so no pressure on the engine builder

I'm guessing then, the spec is something like whirlwind induction, these worked inlets, some work to the heads?, exhaust manifolds and system and a remap?

Would love to have a 4.2 pushing out 100bhp per litre!

And I don't really see why you'd go for a 4.5 conversion instead, I thought most 4.5s weren't any more powerful to begin with anyway.

Edited by jammy_basturd on Tuesday 25th November 08:51

[volospian]

jammy_basturd said:

And I don't really see why you'd go for a 4.5 conversion instead, I thought most 4.5s weren't any more powerful to begin with anyway.

Edited by jammy_basturd on Tuesday 25th November 08:51

No, but the common concensus is that the 4.2 is pretty well sorted by default, whilst the 4.5 isn't, so power gains are much easier to get from a "badly tuned" 4.5 than an already sorted 4.2.

My point was more that, if a lot of work is needed on the 4.2 and that cost extends deep into 4 figure territory, then you may as well spend a little more and have your engine rebuilt to 4.5 RR spec and have a nicely refreshed engine to boot.

I mean, my engine is 11 years old. Do I really want to spend several thousand pounds eking out another 40hp and maybe having to rebuild it anyway in 6 months or a year or whatever, or just put that "tuning" money towards a full rebuild and get the whole thing sorted?

[AlVal]

do you know how much the 4.5 conversion is....

http://www.tvrpower.co.uk/ajp.full.php

£6648.37

Edited by AlVal on Tuesday 25th November 11:54

[The AJP Griff]

Markh said:

...
Could be worth contacting Jamie at Castle Race Engines

Theres quite a bit of interesting work going on with 4.2's at the moment.I'm looking forward to seeing what Clives engine will make,particularly with the red rose type work he's doing himself,which you dont normally see on 4.2's,and this is where a significant difference should come from.You could get Jamie to port your 4.2 inlets/do some head work.Have you also considered fitting 4.5 induction to your 4.2?Would like to see some results of doing this Either way i would recommend giving Jamie a call,his work and knowlege of the AJP is superb,and he's very reasonable

Edited by The AJP Griff on Tuesday 25th November 12:51

[volospian]

AlVal said:

do you know how much the 4.5 conversion is....

http://www.tvrpower.co.uk/ajp.full.php

£6648.37

Edited by AlVal on Tuesday 25th November 11:54

Yep, and that's why I asked how much all this 4.2 tuning work would cost, and it's also why I said if those costs were deep into 4 figure territory, it may be better to do a complete rebuild to 4.5 spec.

[The AJP Griff]

volospian said:

AlVal said:

do you know how much the 4.5 conversion is....

http://www.tvrpower.co.uk/ajp.full.php

£6648.37

Edited by AlVal on Tuesday 25th November 11:54

Yep, and that's why I asked how much all this 4.2 tuning work would cost, and it's also why I said if those costs were deep into 4 figure territory, it may be better to do a complete rebuild to 4.5 spec.

The cheapest,and yet still a really nice way to do it,would be to buy a 4.5 engine,get it re-built,then sell the 4.2 to offset some of the cost

[clive f]

I can`t see why you should n`t have a go and rebuilt and tune the 4.2 if you have one, but I suppose the big difference is the cost of labour if you have to pay someone like tvr power or Jamie or Joo ect to do it for you.
but buying a 4,5 isn`t cheap, and then would you put it straight in the car? personally I`d strip the thing and make sure all is as it should be beforehand, the time its taken to do that why not just wip out your existing engine and get stuck in

I`ll be very dissapointed if my engine doesn`t return a good 400bhp, and I would expect to have spent approx £1k on engine internals (parts only) by the time its back together.

[HarryW]

No reason why a well built 4.2 can't make 410-420bhp through ported 4.2 intakes, my 4.5 makes 450bhp through them .

[volospian]

When I first got my Cerb a year ago, I asked the question, and so did a few others, and all threads got the same answer, the 4.2 is already as good as it gets, there's no point in trying to tune it, it would cost a fortune to make more than 380hp tops, learn to drive your car properly and so on.

We had discussions like this:

http://www.pistonheads.co.uk/gassing/topic.asp?h=0...

which basically said that tuning the 4.2 to more than about 380ish wasn't worth the expense.

Now everybody seems to be saying that 400+ should be easily available to 4.2 engines and that the cost would be relatively low... what changed?

PS. I'm not having a go at anybody. I'm glad that people are actually looking at the 4.2 as a serious tuning proposition at last

[trackcar]

Nothing's changed, that advice still stands. Clive is rebuilding his own engine to effectively red rose spec, wth some very nice exhaust manifolds that me and him have been discussing the past few weeks, plus some induction mods and remapped. A good 4.2 with induction porting, a decent exhaust system and remap will make about 380hp. We're hoping the extra special manifolds and the head work clive is doing will make more than the 20hp we need to break 400hp. So it's not cheap when you factor in the engine work and special manifolds .. 400 plus hp on a 4.2 would normally cost you about 6-7 grand?

[julian64]

Its the area under the graph thats important, not the highest point on the graph.

Out of interest has anyone got a photo of a set of modified butterfly rods.

I think the originals are mild steel, but I've made a set out of stainless steel, and am wondering what can be done with a stainless set in view of more pairing down because of more strength.

One of my ideas is sectional butterflies, with no bolts, but with a square rod down the centre.

[trackcar]

What's important is the area under the graph in the rev range you want to use it most .. you could have an increase at 7500rpm and increase the area under the graph, similarly you could have an increase at 1000rpm if you wanted but you'd seldom use either part of the graph but the area under the graph will have increased .. an increase over a broad spread of rev range would be most helpful, so guess what the next cerbera 4.5 induction kit evaluation hopes to address