Engine Durability of Tuned (400+ WHP) 951's
07-20-2023, 10:58 AM
#331
Rennlist Member
Thread Starter
This purely my approach & my opinion - so of course many may disagree - I'm not big on non-sustainable "sprint" modifiications such as nitrous & methanol injection. For a road car the development processes followed by the factory are a good guide.
I'm not aware of any production Porsche road car using methanol injection.
If you size your lubrication system, oil cooling, engine cooling, fuel system and intercooling right - then measures like methanol injection should be unnecessary.
As I've stated before - for a fixed budget, I'd rather have a dry-sumped engine with massively uprated oil cooling, intercooling , fuel system & engine cooling - producing a reliable 400 - 500 fwhp, which can produce that power continuously without any concerns - rather than a wet-sumped 3 litre, 16 valve, 600+ fwhp "sprint" engine which can only be run at maximum power for short periods before there are well-founded concerns for its healthy & longevity.
The question I ask myself is: "What would the factory do?"
If you look at the 911 Turbo S, GT3 & GT2 RS - the answer is to move towards motorsport-grade systems for all key engine functions - dry sumping, huge oil coolers, huge intercoolers, plenty of headroom in the fuel system, upgraded transmission cooling, larger intercoolers, sophisticated engine management, top quality pistons, rods & valve-train components & meticulous assembly.
I'm not aware of any production Porsche road car using methanol injection.
If you size your lubrication system, oil cooling, engine cooling, fuel system and intercooling right - then measures like methanol injection should be unnecessary.
As I've stated before - for a fixed budget, I'd rather have a dry-sumped engine with massively uprated oil cooling, intercooling , fuel system & engine cooling - producing a reliable 400 - 500 fwhp, which can produce that power continuously without any concerns - rather than a wet-sumped 3 litre, 16 valve, 600+ fwhp "sprint" engine which can only be run at maximum power for short periods before there are well-founded concerns for its healthy & longevity.
The question I ask myself is: "What would the factory do?"
If you look at the 911 Turbo S, GT3 & GT2 RS - the answer is to move towards motorsport-grade systems for all key engine functions - dry sumping, huge oil coolers, huge intercoolers, plenty of headroom in the fuel system, upgraded transmission cooling, larger intercoolers, sophisticated engine management, top quality pistons, rods & valve-train components & meticulous assembly.
07-20-2023, 12:24 PM
#332
Drifting
I sent you a PM about the brake calipers Penguin.
I do wonder about the longevity of 500+ bhp engines running without a dry sump set up.
I do wonder about the longevity of 500+ bhp engines running without a dry sump set up.
Last edited by blade7; 07-20-2023 at 12:26 PM.
07-21-2023, 05:21 AM
#334
As I've stated before - for a fixed budget, I'd rather have a dry-sumped engine with massively uprated oil cooling, intercooling , fuel system & engine cooling - producing a reliable 400 - 500 fwhp, which can produce that power continuously without any concerns - rather than a wet-sumped 3 litre, 16 valve, 600+ fwhp "sprint" engine which can only be run at maximum power for short periods before there are well-founded concerns for its healthy & longevity.
Any 944-based engine running "continuously" 500 rwhp will blow up sooner than later, and a 2.5 8V will not even get there unless totally sacrificing "everyday usability" depending on what this means.
JET951 probably has the most significant reliability record with his wet sump 3.0 16V, used on both the road and track, I guess thanks to not being too greedy with high rev use and using a large 993 oil cooler.
07-21-2023, 08:50 AM
#335
Rennlist Member
Thread Starter
As asked at the start of this thread do we have. any data on 951's at the 400+ whp level which have been driven at last 50,000 miles in this state of tune.
I'm somewhat sceptical of the ability of the Nikasil bores ability to retain roundness and zero taper at for 100,000 miles at the 400+ whp level.
If Porsche had been designing the M44/51 & M44/52 for 400+ whp or around 500 fwhp I very much doubt they would have gone with an open deck, nikasil bores and a wet-sump - imagine the warranty claims.
I'm somewhat sceptical of the ability of the Nikasil bores ability to retain roundness and zero taper at for 100,000 miles at the 400+ whp level.
If Porsche had been designing the M44/51 & M44/52 for 400+ whp or around 500 fwhp I very much doubt they would have gone with an open deck, nikasil bores and a wet-sump - imagine the warranty claims.
07-21-2023, 08:51 AM
#336
As asked at the start of this thread do we have. any data on 951's at the 400+ whp level which have been driven at last 50,000 miles in this state of tune.
I'm somewhat sceptical of the ability of the Nikasil bores ability to retain roundness and zero taper at for 100,000 miles at the 400+ whp level.
If Porsche had been designing the M44/51 & M44/52 for 400+ whp or around 500 fwhp I very much doubt they would have gone with an open deck, nikasil bores and a wet-sump - imagine the warranty claims.
I'm somewhat sceptical of the ability of the Nikasil bores ability to retain roundness and zero taper at for 100,000 miles at the 400+ whp level.
If Porsche had been designing the M44/51 & M44/52 for 400+ whp or around 500 fwhp I very much doubt they would have gone with an open deck, nikasil bores and a wet-sump - imagine the warranty claims.
Had an oil pressure failure.
07-21-2023, 09:36 AM
#339
Rennlist Member
Thread Starter
Ealoken,
350 whp for 80,000 km is impressive.
Assuming 15% transmission losses that's 403 fwhp - which I consider to be serious power from a tuned 2.5 litre M44/51 or M44/52.
Any issues over that period?
Oil consumption, compression, hot & cold starting, EGT's, smooth running, acceptable AFR's - all good?
When you stripped the engine, did you measure the bores?
Any scoring?
How as bearing wear on the mains & big ends?
Valves in good condition?
350 whp for 80,000 km is impressive.
Assuming 15% transmission losses that's 403 fwhp - which I consider to be serious power from a tuned 2.5 litre M44/51 or M44/52.
Any issues over that period?
Oil consumption, compression, hot & cold starting, EGT's, smooth running, acceptable AFR's - all good?
When you stripped the engine, did you measure the bores?
Any scoring?
How as bearing wear on the mains & big ends?
Valves in good condition?
07-21-2023, 09:40 AM
#340
Ealoken,
350 whp for 80,000 km is impressive.
Assuming 15% transmission losses that's 403 fwhp - which I consider to be serious power from a tuned 2.5 litre M44/51 or M44/52.
Any issues over that period?
Oil consumption, compression, hot & cold starting, EGT's, smooth running, acceptable AFR's - all good?
When you stripped the engine, did you measure the bores?
Any scoring?
How as bearing wear on the mains & big ends?
Valves in good condition?
350 whp for 80,000 km is impressive.
Assuming 15% transmission losses that's 403 fwhp - which I consider to be serious power from a tuned 2.5 litre M44/51 or M44/52.
Any issues over that period?
Oil consumption, compression, hot & cold starting, EGT's, smooth running, acceptable AFR's - all good?
When you stripped the engine, did you measure the bores?
Any scoring?
How as bearing wear on the mains & big ends?
Valves in good condition?
Valve steams was done, used 1L oil on 80L fuel if spirited driving.
oil pressure valve got stuck, o-ring on oil pickup failed.
Crank was done, all bearings shut.
AF was a bit low, 11:1 on 1.4 bar boost.
Hope to get my new 2.5 8v dynoed again after fixing all minor issues, ported head, catcam, forged internals, steel sleeves, gtx3576Gen2. 400-450 whp is the target.
07-21-2023, 10:27 AM
#341
Drifting
07-22-2023, 03:20 AM
#344
Rennlist Member
It's more likely that one could build a motor to run 22psi + reliably on the road but then turn it down for the track. The loads are very different in most cases.
07-22-2023, 03:24 AM
#345