4.2l in Classifieds

[jamieduff1981]

Gents, I've read enough to realise that the 4.2 engine is pretty good and probably as quick as a 4.5 at any UK legal speeds. I've also read enough about the challenges involved in getting 4.5s up to factory claimed power outputs to believe that there are probably a lot of 4.2s which out perform some 4.5s.

Is this feasible though? 435bhp seems a little optimistic from a 4.2 litre with decatted exhausts. I'm not trying to ridicule the seller - I'm just trying to learn more about the 4.2 incase I'm overly restricting myself in shopping for 4.5s. 435bhp from the 4.2 litre (360bhp claimed as standard, yes?) seems a hell of a lot for not a lot of work.

http://classifieds.pistonheads.com/classifieds/use...

[Malam]

435bhp? He's dreaming..

[Bigadz]

That's pretty unrealistic tbh. Like you say the 4.2's normally make good power against the claimed spec, and out of the factory the 4.2 vs the 4.5 is probably quite close.
Healthy 4.2's are upwards of 340-50hp. I think Byker has one of the healthiest around making about 380hp. He has a good exhaust system from the top though - ACT and some other bits done I think. I can't see anything much more than 400hp being possible in the 4.2, wasn't there an AJP 4.2 Griff which made about 395hp??

[Obiwonkeyblokey]

not clear exactly what mods hes made, perhaps give him a buzz, he may no more than some on here, but frankly it does seem high. the standard 4.2 is plenty quick anyway, not sure id want something stretched to its envelope.

[jammy_basturd]

The fact the advert states that the car has been uprated from 390bhp suggests he maybe a little confused?

[Pursyluv]

From memory the AJP Griff made 406bhp and MikeinSheffield's late 4.2 with a small amount of engine work made 396bhp - both on RaceProved's dyno

[robsco]

Yes, 435bhp does sound a little over the top, even a properly mapped 4.5 would struggle to stretch to that sort of output. But then who cares, they're so bloody quick it doesn't matter.

[RichV6]

While everyone is talking about 4.2 power output, anyone any suggestions or tips on building a healthy 4.2?
With the chassis rebuild draining the bank account I can't justify the extra cost of going to 4.5 or4.7 as well. The the original engine although running well needs more than just a refresh,Piston rings are shot which may explain the oil consumption so while that far in might as well have it rebuilt from the crank upwards.

[Gazzab]

APM is the answer. Best value AND best quality builds.
Then over to Joolz for some inlet, exhaust and ecu work? Might hit 390 plus.

[scotty_d]

Gazzab said:

APM is the answer. Best value AND best quality builds.
Then over to Joolz for some inlet, exhaust and ecu work? Might hit 390 plus.

This is what I am doing with mine hope to see around 370 ish and the torque moved down the range a little bit more. Mine made 350 on the last run in standard trim with awful exhaust system.

[Gray_101]

Best I ever got with a few mods was 369 bhp on RP rolling road.

But that was with slightly cracked exhaust manifolds and standard induction.

I think 380 bhp would have been achievable with good exhaust manifolds and ported induction.

[ukkid35]

The owner must have had the car dyno'd to know it's been uprated to '435Bhp' so just a matter of asking to see the sheet.

[Jhonno]

ukkid35 said:

The owner must have had the car dyno'd to know it's been uprated to '435Bhp' so just a matter of asking to see the sheet.

[gruffalo]

ukkid35 said:

The owner must have had the car dyno'd to know it's been uprated to '435Bhp' so just a matter of asking to see the sheet.

There are aslo Dyno's and then there are Dyno's if you see what I mean.

[good40]

gruffalo said:

There are aslo Dyno's and then there are Dyno's if you see what I mean.

Where's the car ah...
"At the end of the day....when all's said an done....d'ya know what I mean?"

[RichV6]

Gazzab said:

APM is the answer. Best value AND best quality builds.
Then over to Joolz for some inlet, exhaust and ecu work? Might hit 390 plus.

The car previously visited Joolz and after porting the inlets and remapping made about 358 with cracked manifolds and standard exhaust, and what looks like rings which were past their best. Treated the car to an ACT exhaust and manifolds but never had it back on the rollers. I know on the road the exhaust made a hell of a difference at high revs over how it was previously. Will probably look at a straight rebuild but will go for a full balance and see if there is any gains to be made cleaning up the combustion chambers and ports. If you like a 4.2 red rose!! I'd like to think I could get 380 plus, but will be happy using less oil. Anyone have the new contact details for Joolz now he's up and running?