rover V8 sprintex charger stuff
Discussion
Hi all, first post on Piston heads.
I have a few sprintex super charger kits, as fitted to classic range rovers by DPR engineering of East Coker, Somerset (Dennis Priddle) back in the 80's / 90's. I run one set up on a 3.9 efi (ex range rover) in a defender and i am just building another 4.2 ex LSE V8. I have two questions, i remember Dennis telling me that the sprintex charger ran best with the low compression ratio of the 4.2 (8.35.1) and therefore he lowered the comp ratio of the 3.9's charger conversions he did, to 8.35.1 as well.
Can anyone explain to why he did this? As its seems the tuners like to run the higher comp ratio's of 10.35.1? I dont really understand enough about how the comp ratio effects the performance and why Dennis dropped his down?
Also and, (i know this is a very long shot), does anyone out there know, what the correct size crank pully was for the 3.9 and 4.2? I have the toothed type set ups and i have in the workshop, a 48 tooth, 50 tooth and a 52 tooth. I also have a 35 tooth from a jag conversion. I think most of the conversations he did, were for RR's but there does seem to be a few TVR's with this blower and what looks like his bracketry. Obviously more teeth, more boost, but with out going into all that, i was trying to get at what Dennis had designed as he did know his stuff.
PS if any one whats any info on how these DPR sprintex's set ups work on the RR V8's or any details of the components, pics etc, i'll help if i can, as i know all this stuff is getting on a bit now and information scarce. I also have the original technical information sheets from DPR if any one wants copies.
Oh and for what its worth on rebuilding these Sprintex's, i asked Dennis about rebuilding one for me, at the last days of DPR, and he told, there was only one guy who had the tools to do it in the UK and he had retired and threw all his kit in the skip! He told me that the biggest problem with rebuilding these was shimming up the bearing and getting this correct, so that when it was at operating temp, it did not seize. He said all the knowledge had gone with the retired guy. I tried for months to find some one else, and drew a blank. If anybody knows any different, please pass on the details as i have one for rebuild.
Or if anybody has a S102 spare, i'm interested!
Thanks
I have a few sprintex super charger kits, as fitted to classic range rovers by DPR engineering of East Coker, Somerset (Dennis Priddle) back in the 80's / 90's. I run one set up on a 3.9 efi (ex range rover) in a defender and i am just building another 4.2 ex LSE V8. I have two questions, i remember Dennis telling me that the sprintex charger ran best with the low compression ratio of the 4.2 (8.35.1) and therefore he lowered the comp ratio of the 3.9's charger conversions he did, to 8.35.1 as well.
Can anyone explain to why he did this? As its seems the tuners like to run the higher comp ratio's of 10.35.1? I dont really understand enough about how the comp ratio effects the performance and why Dennis dropped his down?
Also and, (i know this is a very long shot), does anyone out there know, what the correct size crank pully was for the 3.9 and 4.2? I have the toothed type set ups and i have in the workshop, a 48 tooth, 50 tooth and a 52 tooth. I also have a 35 tooth from a jag conversion. I think most of the conversations he did, were for RR's but there does seem to be a few TVR's with this blower and what looks like his bracketry. Obviously more teeth, more boost, but with out going into all that, i was trying to get at what Dennis had designed as he did know his stuff.
PS if any one whats any info on how these DPR sprintex's set ups work on the RR V8's or any details of the components, pics etc, i'll help if i can, as i know all this stuff is getting on a bit now and information scarce. I also have the original technical information sheets from DPR if any one wants copies.
Oh and for what its worth on rebuilding these Sprintex's, i asked Dennis about rebuilding one for me, at the last days of DPR, and he told, there was only one guy who had the tools to do it in the UK and he had retired and threw all his kit in the skip! He told me that the biggest problem with rebuilding these was shimming up the bearing and getting this correct, so that when it was at operating temp, it did not seize. He said all the knowledge had gone with the retired guy. I tried for months to find some one else, and drew a blank. If anybody knows any different, please pass on the details as i have one for rebuild.
Or if anybody has a S102 spare, i'm interested!
Thanks
My understanding is you have more space to cram the air and fuel in as you are using forced induction. Another reason not to have silly duration and overlap cams cos you just blast it out the exhaust!. We usually settle on low 8s:1. CR. However the engine is softer at lower rpms. The Metro Turbots ran 9.5:1 CR with low boost to give a wider power band. Modern thinking is to use the oxygen in the fuel and run high Crs. They use E85 I believe?
On NA engines with low cr we actually see a power boost at low rpms as the momentum of the air fuel flow crams extra in compared with the lower vol higher CR engine, makes them very sweet for 4x4 offroading.
On NA engines with low cr we actually see a power boost at low rpms as the momentum of the air fuel flow crams extra in compared with the lower vol higher CR engine, makes them very sweet for 4x4 offroading.
Edited by PeterBurgess on Monday 1st April 12:12
Not that much difference iirc. Composite gasket maybe has a volume of 8 cc whereas a tin may be 5 cc. I certainly prefer the composites on a rover engine.
As for the reason for lowering the compression, just imagine 10 people stuffed into a small lift, rubbing shoulders and getting a bit heated. They'd be much more comfortable in a larger lift. The same applies to molecules of petrol :-)
Lastly, rv8 pistons of that era have slotted piston skirts and being that weak are prone to cracking.
As for the reason for lowering the compression, just imagine 10 people stuffed into a small lift, rubbing shoulders and getting a bit heated. They'd be much more comfortable in a larger lift. The same applies to molecules of petrol :-)
Lastly, rv8 pistons of that era have slotted piston skirts and being that weak are prone to cracking.
Update. So after speaking to a fair few people, and messages here, it seems low CR on these RV8's, when supercharged, was to control detonation. But with a modern programmable engine control systems, it not so necessary as it was in the 80's. it seems as long as it under the 1.10 ratio, a mapable ecu should be able to stop the detonation. That's what i've been told anyway, although not proven by my actual experience, so lets wait and see!
Hi there my first post also!
I’m just started yesterday to fit a Dennis Priddle sprintex kit to my old 3.5 Range Rover, a project that has been on the back burner for a long time, but now have some free time.
Any pics or info would be great, just in the stripping down phase at the moment!
I’m just started yesterday to fit a Dennis Priddle sprintex kit to my old 3.5 Range Rover, a project that has been on the back burner for a long time, but now have some free time.
Any pics or info would be great, just in the stripping down phase at the moment!
wub443 said:
Hi all, first post on Piston heads.
I have a few sprintex super charger kits, as fitted to classic range rovers by DPR engineering of East Coker, Somerset (Dennis Priddle) back in the 80's / 90's. I run one set up on a 3.9 efi (ex range rover) in a defender and i am just building another 4.2 ex LSE V8. I have two questions, i remember Dennis telling me that the sprintex charger ran best with the low compression ratio of the 4.2 (8.35.1) and therefore he lowered the comp ratio of the 3.9's charger conversions he did, to 8.35.1 as well.
Can anyone explain to why he did this? As its seems the tuners like to run the higher comp ratio's of 10.35.1? I dont really understand enough about how the comp ratio effects the performance and why Dennis dropped his down?
Also and, (i know this is a very long shot), does anyone out there know, what the correct size crank pully was for the 3.9 and 4.2? I have the toothed type set ups and i have in the workshop, a 48 tooth, 50 tooth and a 52 tooth. I also have a 35 tooth from a jag conversion. I think most of the conversations he did, were for RR's but there does seem to be a few TVR's with this blower and what looks like his bracketry. Obviously more teeth, more boost, but with out going into all that, i was trying to get at what Dennis had designed as he did know his stuff.
PS if any one whats any info on how these DPR sprintex's set ups work on the RR V8's or any details of the components, pics etc, i'll help if i can, as i know all this stuff is getting on a bit now and information scarce. I also have the original technical information sheets from DPR if any one wants copies.
Oh and for what its worth on rebuilding these Sprintex's, i asked Dennis about rebuilding one for me, at the last days of DPR, and he told, there was only one guy who had the tools to do it in the UK and he had retired and threw all his kit in the skip! He told me that the biggest problem with rebuilding these was shimming up the bearing and getting this correct, so that when it was at operating temp, it did not seize. He said all the knowledge had gone with the retired guy. I tried for months to find some one else, and drew a blank. If anybody knows any different, please pass on the details as i have one for rebuild.
Or if anybody has a S102 spare, i'm interested!
Thanks
Good Afternoon, This is also my first post here. I have a few sprintex super charger kits, as fitted to classic range rovers by DPR engineering of East Coker, Somerset (Dennis Priddle) back in the 80's / 90's. I run one set up on a 3.9 efi (ex range rover) in a defender and i am just building another 4.2 ex LSE V8. I have two questions, i remember Dennis telling me that the sprintex charger ran best with the low compression ratio of the 4.2 (8.35.1) and therefore he lowered the comp ratio of the 3.9's charger conversions he did, to 8.35.1 as well.
Can anyone explain to why he did this? As its seems the tuners like to run the higher comp ratio's of 10.35.1? I dont really understand enough about how the comp ratio effects the performance and why Dennis dropped his down?
Also and, (i know this is a very long shot), does anyone out there know, what the correct size crank pully was for the 3.9 and 4.2? I have the toothed type set ups and i have in the workshop, a 48 tooth, 50 tooth and a 52 tooth. I also have a 35 tooth from a jag conversion. I think most of the conversations he did, were for RR's but there does seem to be a few TVR's with this blower and what looks like his bracketry. Obviously more teeth, more boost, but with out going into all that, i was trying to get at what Dennis had designed as he did know his stuff.
PS if any one whats any info on how these DPR sprintex's set ups work on the RR V8's or any details of the components, pics etc, i'll help if i can, as i know all this stuff is getting on a bit now and information scarce. I also have the original technical information sheets from DPR if any one wants copies.
Oh and for what its worth on rebuilding these Sprintex's, i asked Dennis about rebuilding one for me, at the last days of DPR, and he told, there was only one guy who had the tools to do it in the UK and he had retired and threw all his kit in the skip! He told me that the biggest problem with rebuilding these was shimming up the bearing and getting this correct, so that when it was at operating temp, it did not seize. He said all the knowledge had gone with the retired guy. I tried for months to find some one else, and drew a blank. If anybody knows any different, please pass on the details as i have one for rebuild.
Or if anybody has a S102 spare, i'm interested!
Thanks
I stumbled across your post whilst on the hunt for more information about the DPR Sprintex conversions.
Myself and a mate are building an offroad buggy, fully fabricated frame/chassis Unimog axles and a DPR 3.5 RV8 engine up the rear. I'll post a link below to it running.
It was a conversion carried out late 80's early 90's to a brand new RRC, we got the engine with about 78k on it and still running sweetly. she was orginally fitted with a flapper sytem, i have upgraded to hotwire running a 3.9 non cat map.
we are now planning to replace the hotwire system with Speeduino for more efficiency and to improve the ignition system.
It's certainly a fun project and we're now not far off of having her out of the workshop for testing.
https://www.youtube.com/watch?v=jDdg44nGbWI
Sounds low, but you give zero details about the build itself, has it been tuned properly, what size blower is it ?
All the usual stuff applies, capacity, heads, cam, intake, exhausts, proper tuning, sensible CR etc etc
it's a rather unusual and perhaps restrictive air inlet there ? Why draw air from a wheel well ?
If whatever boost you're using is generating too much heat, charge cooling is rarely a bad thing. What are charge temps like ?
Can you spin the blower faster ?
But that's a very tidy looking engine compartment.
All the usual stuff applies, capacity, heads, cam, intake, exhausts, proper tuning, sensible CR etc etc
it's a rather unusual and perhaps restrictive air inlet there ? Why draw air from a wheel well ?
If whatever boost you're using is generating too much heat, charge cooling is rarely a bad thing. What are charge temps like ?
Can you spin the blower faster ?
But that's a very tidy looking engine compartment.
That's a very tidy installation. It may be worth checking the pressure upstream of the blower to see whether there is any restriction on the intake - that hose into the air box looks on the small side. The air box itself is in the high pressure bubble in front of the windscreen so not a bad place to draw air from when moving, although it will get very hot stationary. It would also be worth measuring the air temperature at the plenum. With the pipe so close the manifold, I suspect you may get more charge heating than cooling. Water injection is a very easy way to deal with temperature spikes for low boost levels. Do you have a recirc valve to short-circuit the blower when it is off boost?
Thanks guys.
Did write much as I wasn’t sure the thread would be seen.
So the engine is a 3.5 I believe it has composite head gaskets to lower the comp
The air filter was always there I made the air box it gets air from over the lip of the bonnet as you said and although you can’t see it there are two 50mm silicon pipes that suck air from the front air dam just inside of the driving lights.
I have an aquamist water injection running 50/50 water methanol.
Power is really good although it seems to run out of puff at the top so in the high 4K rpm there is only a 10 hp gain the the end. I’ll post the graph.
As I said I want to do something to the engine I’m not sure how old the cam is and what would be the best combination baring in mind it is an original haughins SX so I’d like to keep it that way..... preferably
Thanks
Did write much as I wasn’t sure the thread would be seen.
So the engine is a 3.5 I believe it has composite head gaskets to lower the comp
The air filter was always there I made the air box it gets air from over the lip of the bonnet as you said and although you can’t see it there are two 50mm silicon pipes that suck air from the front air dam just inside of the driving lights.
I have an aquamist water injection running 50/50 water methanol.
Power is really good although it seems to run out of puff at the top so in the high 4K rpm there is only a 10 hp gain the the end. I’ll post the graph.
As I said I want to do something to the engine I’m not sure how old the cam is and what would be the best combination baring in mind it is an original haughins SX so I’d like to keep it that way..... preferably
Thanks
First steps if you aren't wanting major upgrades.
What is the blower actually capable of ? Is it at its limit, or is it capable of much more ?
You could stick a pressure sensor both prior to, and just after the throttle to see if there is any restriction in that area.
Camshaft, there may be good room form gains there, depending what you actually have now, but playing with the cam if nothing else, could certainly help move any power band if you wanted more rpm's ( with supporting valvetrain mods )
If you're not using a lot of boost....what is the CR ? Does it need to be as low as whatever it is, or could you go higher ?
With modern engine control and WI, you may be able to go higher.
Again, log charge temps after the blower, although it may be difficult to install some sort of charge cooling.
What is the blower actually capable of ? Is it at its limit, or is it capable of much more ?
You could stick a pressure sensor both prior to, and just after the throttle to see if there is any restriction in that area.
Camshaft, there may be good room form gains there, depending what you actually have now, but playing with the cam if nothing else, could certainly help move any power band if you wanted more rpm's ( with supporting valvetrain mods )
If you're not using a lot of boost....what is the CR ? Does it need to be as low as whatever it is, or could you go higher ?
With modern engine control and WI, you may be able to go higher.
Again, log charge temps after the blower, although it may be difficult to install some sort of charge cooling.
Oz2 said:
Thanks for your help.
I am looking at better flowing heads an a fast road cam with no overlap.
Charge temps are difficult to measure as they drop considerably when the water injection kicks in, the harder I go the cooler it runs. But I will try to log it on the laptop
Taking out overlap may help the bottom end but absolutely killed the top end on mine. I suspect you may find a tame road cam is the best compromise.I am looking at better flowing heads an a fast road cam with no overlap.
Charge temps are difficult to measure as they drop considerably when the water injection kicks in, the harder I go the cooler it runs. But I will try to log it on the laptop
How much boost are you running; how hot is the charge getting without WI? At 10 PSI mine gets hot very quickly on boost even with lots of WI/meth.
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