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What Power/Chip Would You Go For On a Standard'ish C20LET.....

2K views 75 replies 13 participants last post by  rodgerq 
#1 ·
C20LET
Fully rebuilt/ and cleaned.
Large Intercooler
Turbo Fully rebuilt (0 miles)

What Phs chip would people go for?
what power you you be able to run?

Theres a Nova in the for sale section and hes running 299bhp@15psi and 284 lb ft of torque on EDS Phase 3 Kit
 
#52 ·
Rob@RSC said:
adjusts timing on 1 cylinder? does it have a little arm that moves the contacts in the dizzy?
the sensor isnt 'handed' either so it may be able in ideal conditions be able to sense 2&3 apart from 1&4, but it wont say which ones which so if anything it could retard pairs, but in fact it just retards
Rob, if I haven't got a clue I just say so mate.

If I do have a clue, I expect people to take it as fact, not mock in the dark, hoping that they'll stab something;)
 
#54 ·
Actually I meant exactly what I said.
The Motronic knows for example that cyl#4 just knocked, and it retards the ignition from just on cyl#4 down to X degrees(following the recovery cycle step by step all the way up to X+3 degrees say).
It then remembers that cyl#4 can only handle X+3 so when you restart the engine cyl4 uses the value X+3 as the ceiling.

(It doesn't force a blanket retard to all and sundry)
 
#55 ·
Back on topic, you can spend a fortune, and many do, on making your LET 'safe'. I've got P3.5, made 333bhp (on an optimistic RR). Got ARP rod bolts, standard pistons, rods, head gasket and clutch. It might fail tomorrow, it might not, the same could be said for it whatever the spec. A rebuild costs less than a set of steel rods so I'm happy to take my chances.

Also has 440 injectors @3 bar, stage 1 hybrid turbo from turbo dynamics (basically just got a slightly bigger compressor), ChrisB ported head, EDS intercooler.

Putting a mileage on how long it might last is a hopeless task. I put a lot of miles on mine, but its mostly gentle commuting. If I only drove it flat out it would obviously last a lot less.
 
#56 ·
JohnA said:
Actually I meant exactly what I said.
The Motronic knows for example that cyl#4 just knocked, and it retards the ignition from just on cyl#4 down to X degrees(following the recovery cycle step by step all the way up to X+3 degrees say).
It then remembers that cyl#4 can only handle X+3 so when you restart the engine cyl4 uses the value X+3 as the ceiling.

(It doesn't force a blanket retard to all and sundry)

All fantastic and very clever stuff in terms of making your engine reliabley limp on with a fault, but id sooner just be alerted to the fact i had a fault and then i fix it and go back to full power.
 
#57 ·
chip said:
All fantastic and very clever stuff in terms of making your engine reliabley limp on with a fault,..
This has nothing to do with limp mode, it's standard procedure to make sure that ignition advance is always optimal for every single cylinder.

To enable limp-mode it needs to knock for a few consequitive cycles despite the 8.5 degrees of full initial retard
 
#58 ·
By limping home, i didnt mean "limp mode" on the ecu, i merely meant that if i has to retard the timing on one cylinder its because there is a fault on that cylinder, and therefore isnt at full power any more.
 
#59 ·
chip said:
By limping home, i didnt mean "limp mode" on the ecu, i merely meant that if i has to retard the timing on one cylinder its because there is a fault on that cylinder, and therefore isnt at full power any more.
That is not a fault.
It is dynamically increasing advance until the very limit, and keeping it on the edge, even if that limit shifts.
It shows how advanced the Motronic is, despite its age.
Most aftermarket ECUs are nowhere near as sophisticated.
Processor power is not the end all and be all.
 
#60 ·
Thats not quite true though is it john?

Or are you telling me that if i get a standard LET, then fit a thicker head gasket and drive it around that the ECU will automatically advance the ignition to take advantage of the new lower CR?
 
#62 ·
I know about the injectors, as it uses the narrow band sensor to see how much to skew the map by, but i wasnt aware it could advance the ignition beyond the factory limits, i thought it only ever retarded it.

So if i drop my cr to 7.5:1 and run 105 octane fuel, it will dial in an extra 15 degree (or whatever) of timing then?
 
#64 ·
Ill stick with my aftermarket than thanks mate.

It is my opinion that the moronic does its job very well, but its job is to keep the engine running, not to allow me to modify it for more power.
 
#65 ·
i read that motronic knock article too john, just telling you it retards the lot - imagine if i programmed 1 cylinder on my mbe to fire at a different point, it wouldnt run well with 1 cylinder producing about 10bhp less than the other 3. the ecu light comes on, all 4 are knocked back by 3 degrees and engine power goes right out the window...thats whats PROGRAMMED. it tells you what cylinder is down on some fault codes, but it doesnt retard just the 1. the 2.7 and 2.8 i dont know about cos the company that undid the 2.5 code didnt do them, but the article was on an audi something or other if memory serves and i am not sure it translates across.
i was having a laugh with the moving contacts comment :rolleyes: :p you lot take this far too seriously lmao
 
#66 ·
youd be surprised the "silly" but impressive bits of code in ECUS lol

i mean the diesels we are working on now have the injector codes scanned in at production/change and the ecu can determine the characteristics of each injector and adjsut the fueling map for each one. Im currently working on the MAF adaption whereby the signal from the MAF sensor is slewed over the milage of the engine depending on the Veff changing caused by FIATs bad placing of the air intake snorkel lol

not sure how far ford let their ignition advance but i think it covers a hefty range to allow for things like HCCI running and other fun things to do with diagnostics and emissions
 
#68 ·
JohnA said:
It will actually, within the boundaries of adaptive learning ofcourse.

How else do you think it can pulse injectors 50% larger than the stock ones, when it was not even meant to run anything but stock injectors/fuel pressure?
Hmmmmm interesting point John. Obvioucly the adaptive learning features of the Bosch are workable but it does begger some pretty seraching questions though!

You dont happen to have any Bosch articles lying around do you that describe the LET ecu system in detail (its parameters im after). I cant seem to get any material from Bosch UK relating to anything that old :mad:

Cheers matey, :beer:
 
#70 ·
Dave BB said:
Hmmmmm interesting point John. Obvioucly the adaptive learning features of the Bosch are workable but it does begger some pretty seraching questions though!

You dont happen to have any Bosch articles lying around do you that describe the LET ecu system in detail (its parameters im after). I cant seem to get any material from Bosch UK relating to anything that old :mad:

Cheers matey, :beer:


See my website under "flogging a very old almost dead horse"
 
#72 ·
trouble is that bosch built the units and gm subcontracted the work on them for opel so without disassembling each variation you cannot say what code it has been given...think i am right in saying that since i know the vw/gm ecu works in a very different way with different sensors and yet was under the same bosch ecu 'banner'
 
#73 ·
BeArDy,

Going back to the original question....

With an engine in decent condition, and a large intercooler and exhaust, my Cally turbo has just made 258 Bhp, and 289lb ft of torque with the EVO2 software.

I know the power is less than you were hoping, but the torque is very usable for a road car, and the engine should be relatively reliable.

Just thought I'd let you know that the lesser software CAN still give quite good results.
 
#74 ·
JohnA said:
You definately need it while running on the ragged edge of detonation, but the Motronic knock system is better (but hidden!)
i'll be running aftermarket here, but i am of the thinking that i wont be running my engine on the very edge of the risk of it detting to bits. i am doing my best to modify it in other ways to make power other than high boost, loads of advance or the use of a high octane fuel. Good VE is right up there on my priority list - one of the reasons i chose TBs among other seemingly small things but they should all add up to give me what im after.

im hoping to be able to get mine mapped so its still making great power/torque but still well within the realms of its safety margins. heres hoping it can be done.

rodgerq
 
#76 ·
yeah ill be tryin my best to keep that to a minimum. and the mapper will also be informed that i dont want it mapped for out and out power(although a spare map for that would be handy :D ) but to map it for some reliability aswell.

rodgerq
 
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