Engine swap

boywholovedbooks

Junior Member
Messages
63
I have a QP 4.2 2009, looking to swap an engine to either 4.7 or 4.7 Sport GTS. Already installed 4.7 sport GTS oval backboxes, but kept the central resonator, don't like cheap shouting noise...

The QP 4.7 Sport GTS are incredibly rare engines to find, but i have managed to source a Granturizmo 4.7 Auto S, both vehicles being equipped with ZF gearbox.

My question is as am in the UK, so right hand drive and the GT 4.7 Auto S engine is in the US, which is left hand drive, would it fit into my QP? The ECU for GT Auto S will be supplied by the seller too.

I should also mention that particular engine from Granturizmo 4.7 Sport S has got 460 bhp/384ft torque as opposed to 4.7 Sport GTS 450 bhp and 361ft torque.... Whilst power wise they could be similar, i think Granturizmo 4.7 Sport S has a slightly more menacing sound, which, combined with oval exhausts from 4.7 Sport GTS could be a symphony to listen :)

Thanking in advance.

Kind regards

Yev
 
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2b1ask1

Special case
Messages
20,220
That’s a whole can ’o’ worms you’re opening for yourself. If you know how to work CAN-BUS you might be able to do it but I know to my own cost it is not going to be in the slightest bit easy and you will not get any help from the manufacturer in any form. From my experience with Peugeot they were positively obstructive.
 

Ebenezer

Member
Messages
4,445
There was a QP advertised a few years ago now that had had its 4.2 replaced by a 4.7 so it can be done, but I think it was extremely technical.
All the talk was how would the new owner get it insured!
Eb
 

Zep

Moderator
Messages
9,110
To answer your question, the engines have the same block and layout, so it will more than likely fit in the space. Getting the ECUs to talk is likely to be much more of a challenge, it’s not clear that the engine ECU even has the same plug. Not for the faint of heart!
 

boywholovedbooks

Junior Member
Messages
63
To answer your question, the engines have the same block and layout, so it will more than likely fit in the space. Getting the ECUs to talk is likely to be much more of a challenge, it’s not clear that the engine ECU even has the same plug. Not for the faint of heart!
I will check the plug/connector with the seller. Essentially it is the same engine....
 

Zep

Moderator
Messages
9,110
I will check the plug/connector with the seller. Essentially it is the same engine....

Essentially yes. The devil is going to be in the detail. The ECU is matched to the other components in the car, so it definitely won’t just plug in and work.
 

conaero

Forum Owner
Messages
34,593
So the issues are, you can’t replace an Auto engine with an MC shift engine as the cranks are different as is the engine timing and vice versa

So MC shift for MC shift or Auto for Auto will work.

You will need the loom and the ecu from the donor engine.

Would it not be simpler and more cost effective to sell the 4.2 and buy a 4.7? That would be my advice as the unknown tents to strip the wallet.
 

midlifecrisis

Member
Messages
16,102
So the issues are, you can’t replace an Auto engine with an MC shift engine as the cranks are different as is the engine timing and vice versa

So MC shift for MC shift or Auto for Auto will work.

You will need the loom and the ecu from the donor engine.

Would it not be simpler and more cost effective to sell the 4.2 and buy a 4.7? That would be my advice as the unknown tents to strip the wallet.
The cranks are different? Or do you mean the crankcases to accept the gearbox?
 

MarkMas

Chief pedant
Messages
8,795
....Would it not be simpler and more cost effective to sell the 4.2 and buy a 4.7? ....

That's what I did.

The buy/sell 'gap' between like-for-like 4.2 and 4.7S would be about £2,000-6,000. BUT I suppose you risk swapping a car you know for something that might have unknown gremlins. So perhaps add a 'contingency' of £0 to £5,000 to that.
 

boywholovedbooks

Junior Member
Messages
63
So the issues are, you can’t replace an Auto engine with an MC shift engine as the cranks are different as is the engine timing and vice versa

So MC shift for MC shift or Auto for Auto will work.

You will need the loom and the ecu from the donor engine.

Would it not be simpler and more cost effective to sell the 4.2 and buy a 4.7? That would be my advice as the unknown tents to strip the wallet.

Thank you, yes, i know that it should be ZF gearbox, that is exactly what those two engines are. ECU from donor vehicle is also present, i have requested the seller to send me the photo of the connector. Thank you for advice about the loom, will ask the question, but doubt he will have that.

Not really cost effective, my 4.2 2009 has about 120.000 miles on it and will not fetch anything more than 10K. 4.7 sport GTS will cost at least 25K. I also invested about 10K into my vehicle doing all sorts of repairs, bought it for 7.5K, so 17.5K altogether so far.

The engine i have found is being sold at around 4K including ECU + shipping to UK + clearance. So hope to do everything around 5K + installation about 2K.

The other thing is i like my colour combination, blue oceano and cream leather saloon seats, unfortunately i have not seen a single 4.7 Sport GTS in the same colour combination. I also do not like the suspension on 4.7 Sport GTS, it is much stiffer than on mine.
 

boywholovedbooks

Junior Member
Messages
63
That's what I did.

The buy/sell 'gap' between like-for-like 4.2 and 4.7S would be about £2,000-6,000. BUT I suppose you risk swapping a car you know for something that might have unknown gremlins. So perhaps add a 'contingency' of £0 to £5,000 to that.
You have got 4.7S, the vehicle am talking about is 4.7 Sport GTS. They are trading on AutoTrader between 25K - 45K, depending on year/condition. Agree about the gremlins, i know my car inside out, bought it for 7.5K, invested about 10K more to bring it to perfect road worthy condition. So yes, if i go for 4.7S, i have seen some around 12K on autotrader, however 4.7 Sport GTS would be at least 24K + the gremlins....
 

boywholovedbooks

Junior Member
Messages
63
To answer your question, the engines have the same block and layout, so it will more than likely fit in the space. Getting the ECUs to talk is likely to be much more of a challenge, it’s not clear that the engine ECU even has the same plug. Not for the faint of heart!
Thank you, i have requested the photo of the ECU plug from the seller, will check. The engines are the same, i was not sure about RHD vs LHD settings...
 

Ebenezer

Member
Messages
4,445
Repaint and swap the insides. Got to be cheaper and easier than transplanting the engine. But we are all reaching for the popcorn! There's a chap who stuck a 4.7 into a TVR so he must know a thing or two about the electronics.
Eb
 

boywholovedbooks

Junior Member
Messages
63
Repaint and swap the insides. Got to be cheaper and easier than transplanting the engine. But we are all reaching for the popcorn! There's a chap who stuck a 4.7 into a TVR so he must know a thing or two about the electronics.
Eb
can not find the post, maybe that guy knows someone that could do it.....
 

MarkMas

Chief pedant
Messages
8,795
You have got 4.7S, the vehicle am talking about is 4.7 Sport GTS. They are trading on AutoTrader between 25K - 45K, depending on year/condition. Agree about the gremlins, i know my car inside out, bought it for 7.5K, invested about 10K more to bring it to perfect road worthy condition. So yes, if i go for 4.7S, i have seen some around 12K on autotrader, however 4.7 Sport GTS would be at least 24K + the gremlins....

Ah, yes, well the GT S model seems to be at silly money now. And as you say, almost none in sensible colours. Those both contributed to my thinking that 4.7S would be 'enough' (which it is, for me).

But I'm also thinking there are reasons why the GT S comes with stiffer suspension and better brakes. So putting that engine into a standard 4.2 might bring interesting on-the-road challenges. But for the right person , a fun project ! Keep us posted with how it goes.
 

MarkMas

Chief pedant
Messages
8,795
Repaint and swap the insides. Got to be cheaper and easier than transplanting the engine. But we are all reaching for the popcorn! There's a chap who stuck a 4.7 into a TVR so he must know a thing or two about the electronics.
Eb

Yes, it does feel like a re-trim and a wrap might be easier than an engine swap. But what do we know, Eb? Nothing, TBH.
 

boywholovedbooks

Junior Member
Messages
63
Ah, yes, well the GT S model seems to be at silly money now. And as you say, almost none in sensible colours. Those both contributed to my thinking that 4.7S would be 'enough' (which it is, for me).

But I'm also thinking there are reasons why the GT S comes with stiffer suspension and better brakes. So putting that engine into a standard 4.2 might bring interesting on-the-road challenges. But for the right person , a fun project ! Keep us posted with how it goes.
Apparently, the engine is heavier, that is one of the reasons, more power too. My brakes and calipers are the same as GT S (i did upgrade earlier), so it is just a question of the engine and perhaps suspension if need be. The Granturismo 4.7 Auto S engine is apparently lighter than that of QP 4.7 GT S, so if all goes to plan, i would have hoped not to change the current suspension....
 

Scaf

Member
Messages
6,512
Brave project but your car, your skills your decision.
Loads of people do things because they can, not because the are the most sensible thing to do.
Make sure you keep us updated on progress and don’t forget there are some clever people on here with deep technical knowledge about these cars that will always try to help.
Good Luck !
 

Gazcw

Member
Messages
7,699
Apparently, the engine is heavier, that is one of the reasons, more power too. My brakes and calipers are the same as GT S (i did upgrade earlier), so it is just a question of the engine and perhaps suspension if need be. The Granturismo 4.7 Auto S engine is apparently lighter than that of QP 4.7 GT S, so if all goes to plan, i would have hoped not to change the current suspension....
Pretty sure they are all the same engines and boxes. Where's Matt when you need him?
Just the gearbox and engine ecu that provide the differences ie. Gts get launch and faster shifts when the S did not. Is an extra 10bhp worth the added cost of buying a 'gts' engine over an s , I doubt that very much.
Changing from skyhook to fixed would be a better solution for carrying speed round the twisties.