Reducing Det???
Discussion
Probably not the right forum for this, but the Engines forum doesn't receive much in the way of traffic...
Just wondering how to make an engine more det prone, and if what the gains could be?
Looking to build a Peugeot XU10 twin cam hybrid (mix of XU10J4/R/R and XUJ4 with a turbo, and with good squish (0.9mm) I'm looking at ~9.3:1 compression.
Ideally I's like to run it on BP 95, and from what I gather a ceramic coated twin scroll manifold and decent-ish cam profiles (I'm limited to stock pug profiles )will help.
Obviously Nimonic exhaust valves help, (is 100+ plus readily available?) as do trojan valve seats and guides, polished combustion chambers, and oil sprayed pistons ( the more the better).
How about extra water lines in the head to cool it down?
Any turbo recommendations up to 400hp+ (twin scroll preferred)? and any other trips and ticks to allow me to run more boost?
I was thinking of the Borg Warner S200 range or the Mitsubishi twin scrolls?
Any advance on this? Also, what ECU and supporting mods for the safest, most reliable most durable 400hp available? Not interested in a pissing contest TBH
Will a stock XU10J4RS block and rods suffice?
Also, I was wondering if there is an ideal ignition angle for engines in general, and if it's possibly related to bottom end geometry. Most OEMs "seem" to vary comp and boost instead - giving the impression there's some magic optimal ignition figure I don't know about yet!
Just wondering how to make an engine more det prone, and if what the gains could be?
Looking to build a Peugeot XU10 twin cam hybrid (mix of XU10J4/R/R and XUJ4 with a turbo, and with good squish (0.9mm) I'm looking at ~9.3:1 compression.
Ideally I's like to run it on BP 95, and from what I gather a ceramic coated twin scroll manifold and decent-ish cam profiles (I'm limited to stock pug profiles )will help.
Obviously Nimonic exhaust valves help, (is 100+ plus readily available?) as do trojan valve seats and guides, polished combustion chambers, and oil sprayed pistons ( the more the better).
How about extra water lines in the head to cool it down?
Any turbo recommendations up to 400hp+ (twin scroll preferred)? and any other trips and ticks to allow me to run more boost?
I was thinking of the Borg Warner S200 range or the Mitsubishi twin scrolls?
Any advance on this? Also, what ECU and supporting mods for the safest, most reliable most durable 400hp available? Not interested in a pissing contest TBH
Will a stock XU10J4RS block and rods suffice?
Also, I was wondering if there is an ideal ignition angle for engines in general, and if it's possibly related to bottom end geometry. Most OEMs "seem" to vary comp and boost instead - giving the impression there's some magic optimal ignition figure I don't know about yet!
Edited by Luther Blisset on Sunday 22 December 21:09
Any forced induction is going to be knock limited on pump fuel so the best you can do is drop the static compression ratio like you suggest, reduce intake temperature by fitting a big intercooler and running the best fuel you can, preferably 98Ron or E85 equivalent. Water or meth injection will also help keep detonation under control but ultimately the safety margin is dictated by how good your tune is. Detonation is bad.
Phateuk said:
Thought the same 
TBH I have no idea what you're referring to 
My mistake for the misleading content, hope the title gave the game away though...littleredrooster said:
Luther Blisset said:
Just wondering how to make an engine more det prone, and if what the gains could be?
If I'm reading this right...why on earth would you want to build an engine which was more prone to detonation? Are you sure you read this sentence before you posted it?Max_Torque said:
er, i think you mean "less" not "more"..........
It's saturday night, forgive me! You don't wanna know how many times I had to run spell check lol 
But you're dead right - I did mean less det prone!
So, for someone who doesn't have a multi million dollar R&D budget - any pearls of wisdom?
Luther Blisset said:
Phateuk said:
Thought the same
TBH I have no idea what you're referring to My mistake for the misleading content, hope the title gave the game away though...littleredrooster said:
Luther Blisset said:
Just wondering how to make an engine more det prone, and if what the gains could be?
If I'm reading this right...why on earth would you want to build an engine which was more prone to detonation? Are you sure you read this sentence before you posted it?Max_Torque said:
er, i think you mean "less" not "more"..........
It's saturday night, forgive me! You don't wanna know how many times I had to run spell check lol But you're dead right - I did mean less det prone!
So, for someone who doesn't have a multi million dollar R&D budget - any pearls of wisdom?
Simes205 said:
Stick this on 205gtidrivers.com
Fair point. Apart from Max Torque and a few others, the rest want to prove their intelligence by abandoning common sense and nitpicking. Nice way to spend your saturday evening for some I guess lol. Soerry to the genuine helpers for being a touch well oiled, but I'm fighting it off lolSAhame there's such a waiting list a so much jumping through hoops tough eh? I guess I could learn a bit from Eric Yellow's thread, but it's a more high budget approach.
I'll leave the rest of you to can keep debating whether the S-Line or M-Tech kits impresses the Jones's more....
Luther Blisset said:
Fair point. Apart from Max Torque and a few others, the rest want to prove their intelligence by abandoning common sense and nitpicking. Nice way to spend your saturday evening for some I guess lol. Soerry to the genuine helpers for being a touch well oiled, but I'm fighting it off lol
SAhame there's such a waiting list a so much jumping through hoops tough eh? I guess I could learn a bit from Eric Yellow's thread, but it's a more high budget approach.
I'll leave the rest of you to can keep debating whether the S-Line or M-Tech kits impresses the Jones's more....
sorry if this came of a bit arsey, it's the drink lol.SAhame there's such a waiting list a so much jumping through hoops tough eh? I guess I could learn a bit from Eric Yellow's thread, but it's a more high budget approach.
I'll leave the rest of you to can keep debating whether the S-Line or M-Tech kits impresses the Jones's more....
And no, this isn't Welshbeef II. This is a one off I swear.
I know when to stop digging - it's usually when I'm sober...
I know jack about the particulars of your engine but!
Ensuring you have no sharp corners in your combustion chamber is the start, they are the point where det will start 1st. WI will rob power but allow more advance which will bring more power, catch 22. More advance causes det but this can be controlled with more fuel, again catch 22.
For optimum performance you need to sail very close to the wind regarding fuelling and timing. My advice other than sharp bits in chamber would be to gat the best fuelling set up you can afford. When running close to the edge a momentary hiccough in your fuelling can kill your engine faster than no oil.
Ensuring you have no sharp corners in your combustion chamber is the start, they are the point where det will start 1st. WI will rob power but allow more advance which will bring more power, catch 22. More advance causes det but this can be controlled with more fuel, again catch 22.
For optimum performance you need to sail very close to the wind regarding fuelling and timing. My advice other than sharp bits in chamber would be to gat the best fuelling set up you can afford. When running close to the edge a momentary hiccough in your fuelling can kill your engine faster than no oil.
retropower said:
can't help thinking, with the list that you reel off in the first post, that you already know the answers......
Fair comment, but anything cheaper that I' missing? What makes some engines take big comp and others not? I'm prepared to splash out on the head so to speak, but I'd like to keep within a reasonable budget... this isn't a rallycross engine after all.AFIUI it these things come with 158mm cast rods, with that kinda length is bending a major issue? Is there anything OEM I could swap it with for cheap?
mighty kitten said:
Cheapest gun wash from a paint suppliers has lots of xylene and toluene which is a good way of raising octane levels . 10% by volume when filling up will do . Twin scroll turbo needs a split pulse manifold to work properly
ould like to do it all 95 octane if poss. I know about the cost in power and torque but as I say - it'd not a pissing contest. Still on the look out for a decent Evo 4-9 tubular twin scroll mani to hack up to fit.crossy67 said:
I know jack about the particulars of your engine but!
Ensuring you have no sharp corners in your combustion chamber is the start, they are the point where det will start 1st. WI will rob power but allow more advance which will bring more power, catch 22. More advance causes det but this can be controlled with more fuel, again catch 22.
For optimum performance you need to sail very close to the wind regarding fuelling and timing. My advice other than sharp bits in chamber would be to gat the best fuelling set up you can afford. When running close to the edge a momentary hiccough in your fuelling can kill your engine faster than no oil.
That's another thing! I would like to run the lean side of stoich to improvr economy, maybe richening up once at full boost. Is this a bad idea as |I imagine. Bear in mind I'm building it to take the heat.Ensuring you have no sharp corners in your combustion chamber is the start, they are the point where det will start 1st. WI will rob power but allow more advance which will bring more power, catch 22. More advance causes det but this can be controlled with more fuel, again catch 22.
For optimum performance you need to sail very close to the wind regarding fuelling and timing. My advice other than sharp bits in chamber would be to gat the best fuelling set up you can afford. When running close to the edge a momentary hiccough in your fuelling can kill your engine faster than no oil.
Would an Evo 9 or 10 turbo deliver without lunching itself at 400hp? Or am I better off with a hybrid - billet 16g wheel (spec pulled out of my ass), 360 plate etc...
Take any sharp edges off and valve cut outs on the pistons.
Get the biggest intercooler or charge cooler on you can.
Look at compressor maps - size the turbo so its operating at peak efficiency, too small just means too much heat.
High octane fuel.
Good free flowing exhaust.
Get it mapped by some one who knows what they are doing, uses a knockbox or similar.
Lower compression ratio.
etc
Get the biggest intercooler or charge cooler on you can.
Look at compressor maps - size the turbo so its operating at peak efficiency, too small just means too much heat.
High octane fuel.
Good free flowing exhaust.
Get it mapped by some one who knows what they are doing, uses a knockbox or similar.
Lower compression ratio.
etc
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