P38 Rover V8s

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Henry-b
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P38 Rover V8s

Post by Henry-b »

Hello gents long time no see!

Anyway..

I have a Thor 4.6 P38 and the quoted power is 214hp and 407nm however the Gems is quoted as having more HP but less torque at 225hp and 380nm

Apparently though in America Land Rover got in trouble because the Gems didn't produce near the quoted power level from LR..

My question is does the Thor really produce less than the Gems or is there a mistake somewhere anyone had a P38 on the dyno?

Surely with the more efficient bosch motronic injection and revised intake it would produce more power than the old sagem system? :idea: :?:

Thanks

H



DaveEFI
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Re: P38 Rover V8s

Post by DaveEFI »

The long tract inlet system on the Thor is designed to maximize lower RPM torque, since it is fitted to a 4x4. The original Lucas injection which all the previous engines shared as regards the inlet design was originally meant for the Vitesse, a sports saloon.
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garrycol
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Re: P38 Rover V8s

Post by garrycol »

Yes the Thor produces a little less HP but a bit more torques.

Chicken Drumstick
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Re: P38 Rover V8s

Post by Chicken Drumstick »

DaveEFI wrote:
Fri Oct 08, 2021 10:50 pm
The long tract inlet system on the Thor is designed to maximize lower RPM torque, since it is fitted to a 4x4. The original Lucas injection which all the previous engines shared as regards the inlet design was originally meant for the Vitesse, a sports saloon.
I can see why they'd want a 4x4 to have good low rpm torque. But I've read the 4.6 Thor makes peak power at the red line.

"The Bosch engine is mapped in such a way that it produces maximum power when it hits the Rev Limiter, which is set at 5400 RPM."

Ref: https://www.tornadosystems.com/product/ ... or-engine/

Mine has been on a dyno (rolling road), but would seem to pretty much match this expectation.

I struggle to believe Thors make less power than a GEMS one from the factory, I suspect the Thor solution was the real answer in getting the power up, due to the legal action LR faced in the USA with the early examples.

A bit of a Google also suggest the Thor model is slightly quicker, which would back up the assumption that it makes either the same power or more.

1998 Range Rover 4.6 HSE Vitesse 0-60 mph 9.6 Quarter mile 17.1

1999 Range Rover 4.6 HSE 0-60 mph 9.4 Quarter mile 17.0

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Re: P38 Rover V8s

Post by DaveEFI »

In terms of the electronics, I've no idea how good the Gems system is.

To do a real comparison between the inlet manifold designs, you'd need to use a properly tuned after market ECU with both (like say a MegaSquirt)

Peak power has really not much to do with a standing quarter mile figure (within reason) - it's the torque curve below that which matters for road use. Perhaps even more so with an auto. Different in a race car where you keep the engine on boil.

With the earlier Lucas systems - especially the 4CU flapper - there was quite a variation between samples. The 4CU tended to run weak at lower revs/moderate throttle openings. Perhaps to give the best lab MPG figures. On going MegaSquirt on my SD1, the big difference was the extra grunt at low revs - peak power being much the same. Wouldn't be surprised if this applied to the Gems too.
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SPJersey
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Re: P38 Rover V8s

Post by SPJersey »

I hope I'm posting this in the right place.....
I'm planning an engine swap and looking to decide between a THOR or a BOSCH 4.6 V8 for the project.
Size (height) is my main concern but also the complexity of decoupling the ECU from the BECM; I've heard this can be a challenge.
In a perfect world I'd find a donor P38 with the right engine and manual trans, so I won’t need to source a R380 gearbox & clutch etc separately but they are like hens teeth. I may end up getting a crate engine and taking all the work (and learning) away! apart from cost I want the experience.
I have a few questions if I may:
1) does anyone have access to any CAD files that I can load into Fusion 360 (my son has access and has offered to help with design and fitting etc) for a rover V8 (GEMS or THOR) with a manual R380 Gear box....either complete drivetrain or component CAD files? something like this https://do-it-up.com/wp-content/uploads ... -Image.jpg
2) how easy is it to decouple the ECU from the BECM - I know Megasquirt is an option as is ripping the fuel injection out and putting a carburettor on
3) does anyone have any info as to which donor vehicles to look out for, for the purple unicorn that is a manual 4.6!
4) not looking for a performance set up so may just lift out of donor and put into spitfire and then in the future take engine back out and do a full rebuild over a winter....thoughts on that approach.
Thanks for any insight folk can give.
Regards
SP

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Re: P38 Rover V8s

Post by ChrisJC »

Yeah, I put a Thor engine in my Land Rover, coupled to an R380.
I used Tornado Systems to alter the ECU to a 'standalone' system. The wiring is still complicated - so I did a drawing which I gave them.
Note that you need the right ECU to start with - I think a Discovery II ECU (they will tell you).

You can get flywheels made to suit your Thor + manual transmission. That's easier than trying to find a factory flywheel.

You can fit it straight to an R380 if you use the R380 from any Land Rover product. However the bellhousing is very very long.
I wanted the shortest version possible, so I used an adaptor ring to take it to the Land Rover 4 cylinder bolt pattern, then the 'stumpy' bellhousing from Ashcroft Transmissions.

The clutch is 9.5" though.

Chris.
Attachments
20160810_191355.jpg
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Series IIA 4.6 V8
R/R P38 4.6 V8
R/R L405 4.4 SDV8

Harrylandyv8
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Re: P38 Rover V8s

Post by Harrylandyv8 »

SPJersey wrote:
Tue Jul 11, 2023 7:42 am
I hope I'm posting this in the right place.....
I'm planning an engine swap and looking to decide between a THOR or a BOSCH 4.6 V8 for the project.
Size (height) is my main concern but also the complexity of decoupling the ECU from the BECM; I've heard this can be a challenge.
In a perfect world I'd find a donor P38 with the right engine and manual trans, so I won’t need to source a R380 gearbox & clutch etc separately but they are like hens teeth. I may end up getting a crate engine and taking all the work (and learning) away! apart from cost I want the experience.
I have a few questions if I may:
1) does anyone have access to any CAD files that I can load into Fusion 360 (my son has access and has offered to help with design and fitting etc) for a rover V8 (GEMS or THOR) with a manual R380 Gear box....either complete drivetrain or component CAD files? something like this https://do-it-up.com/wp-content/uploads ... -Image.jpg
2) how easy is it to decouple the ECU from the BECM - I know Megasquirt is an option as is ripping the fuel injection out and putting a carburettor on
3) does anyone have any info as to which donor vehicles to look out for, for the purple unicorn that is a manual 4.6!
4) not looking for a performance set up so may just lift out of donor and put into spitfire and then in the future take engine back out and do a full rebuild over a winter....thoughts on that approach.
Thanks for any insight folk can give.
Regards
SP
Iv got a factory manual v8 4L p38. I had gearbox issues awhile back (lost 5th gear) so I found someone selling an r380 from a diesel p38. After looking at both gearboxes I decided they wouldn't be compatible so traded the diesel r380 for a petrol one which are rare. The p38 r380 also has a different gear selector box on top which moves the gear stick further back. Currently looking at putting a 4.6 block in and sticking with the gems ecu. Maybe just get it mapped

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Re: P38 Rover V8s

Post by SuperV8 »

SPJersey wrote:
Tue Jul 11, 2023 7:42 am
I hope I'm posting this in the right place.....
I'm planning an engine swap and looking to decide between a THOR or a BOSCH 4.6 V8 for the project.
Size (height) is my main concern but also the complexity of decoupling the ECU from the BECM; I've heard this can be a challenge.
In a perfect world I'd find a donor P38 with the right engine and manual trans, so I won’t need to source a R380 gearbox & clutch etc separately but they are like hens teeth. I may end up getting a crate engine and taking all the work (and learning) away! apart from cost I want the experience.
I have a few questions if I may:
1) does anyone have access to any CAD files that I can load into Fusion 360 (my son has access and has offered to help with design and fitting etc) for a rover V8 (GEMS or THOR) with a manual R380 Gear box....either complete drivetrain or component CAD files? something like this https://do-it-up.com/wp-content/uploads ... -Image.jpg
2) how easy is it to decouple the ECU from the BECM - I know Megasquirt is an option as is ripping the fuel injection out and putting a carburettor on
3) does anyone have any info as to which donor vehicles to look out for, for the purple unicorn that is a manual 4.6!
4) not looking for a performance set up so may just lift out of donor and put into spitfire and then in the future take engine back out and do a full rebuild over a winter....thoughts on that approach.
Thanks for any insight folk can give.
Regards
SP
So this is going in a Spitfire? so RWD? in which case P38=4WD R380 and 2WD R380 are quite different and not interchangeable - You would need a 2WD R380 from a Morgan (rather rare) and maybe was in a Sherpa Van? but with too low gearing, or an 2WD LT77 (I have one spare if you interested?) from an SD1/Morgan/TVR etc..
I would think will be easiest to find an engine/box out of a crashed TVR - these used a Tremec T5 in the later versions, LT77 in the earlier versions.
I modified my GEM's inlet to bring the inlet round to the front - rather than side for bonnet clearance.
Dax Rush 4.6 supercharged V8 MSII

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