Autech Pulsar GTi
- Thread starter Dale
- Start date
to a point yeh, hence goin to greg for me next
but human tuning can't put ignition in where the engine won't take it.....and as dave says that can be limited by c/r. In my eyes you get to a point where the lack of ignition going in outweighs the pros from having more compression, so it's a fine balancing act.
I think the Dynamic CR is quite important here...
A 14:1CR SR20DE with C3 Cams has a LOWER Dynamic Compression Ratio (DCR) than a 12.5:1CR SR20VE with N1's.
The SR20DE comes in around 9.5 - 10:1DCR
The SR20VE comes in around 10.5 -11:1DCR
Cranking pressures would be about 20-30psi lower on the DE.
The numbers are rough approximations, but still illustrate the difference between the two and why i believe the DE can get away with a higher static CR.
Dynamic CR is all to do with the intake valve closing point on the compression stroke. As you can see, static CR alone is meaningless.
A 14:1CR SR20DE with C3 Cams has a LOWER Dynamic Compression Ratio (DCR) than a 12.5:1CR SR20VE with N1's.
The SR20DE comes in around 9.5 - 10:1DCR
The SR20VE comes in around 10.5 -11:1DCR
Cranking pressures would be about 20-30psi lower on the DE.
The numbers are rough approximations, but still illustrate the difference between the two and why i believe the DE can get away with a higher static CR.
Dynamic CR is all to do with the intake valve closing point on the compression stroke. As you can see, static CR alone is meaningless.
the way i understand it is, piggy backs/daughter boards modify the signal coming from the standard ecu to the engine, so are always limited to the standard ECU base map, and NO extras.
in my opinion dangerous on anything other than a mild tweaks to a mild cam'd bolt on NA engine, where it is relying on the signal from the 14 year old MAF as the only option.
standalone is the ONLY way to go if the engine is opened
you can create your own base map, even more retarded than the standard ecu base. therefore allowing very high comp to be relatively safe.
especially in this country, as standard fuel is crap, high octane is expensive, and good SR20 tuners are accustomed to big boost applications.
an added bonus also is there will be more engine data than a standard ecu, so if something is wrong, an experienced tuner can see it straight away
"little advert for link"
Thor racing (which sell the link in the UK) have huge experience with Toyota, Beams engine, imagine trying to tune an engine where there are constantly variable cam profiles, rather than a "simple" vtec or VVL ... thats where im going
my 2p :zoidberg:
Steve
my mates Nissan Cefiro with a RB27 hoping to run aroun 600hp is at Thor Racing now, for wiring and mapping!
....if you have deep pockets. Its out of reach for the vast majority of people.
It's not the ONLY way to go, Nistune is a very good alternative to standalone, allowing you to basically alter everything on the stock ECU, so it's pretty much like standalone, but obviously you still have some limitations.
The amount of engine knowledge in this thread is awesome!
It's a bodge bud, and you know it!
Why more people don't use Power FC is beyond me.
http://cgi.ebay.co.uk/Nissan-Pulsar-GTIR-APEXI-Power-FC-ECU-Commander-/280672036946?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item41595b6852
£600 and you have a Stand Alone ECU, that will fit straight into the stock harness (albeit with a few pins swapped over on the harness) and use all stock sensors.
JOB DONE!
fair point, its not the ONLY way to go, but you knew what i meant, in my opinion, its standalone or nothing when starting a big build
Nistune is very good i agree, but without creating your own base map, nothing is "like a standalone"
if dale went standalone right now, without doing anything more to the engine, he would gain that 220whp. bold statement i know, but i think justified, would be great to try it :lol: unfortuately nobody has £1500 handy to spend on someone else's engine
Steve
Buy that ecu dude, 220whp gain, I might even buy it lol!
yeh i'm with dale here, i don't believe for a second that standalone could get dale 220whp now as it is, just from the map - sorry steve 
the safety or area under the curve or smooth-ness of it may be better across the rev range due to the added scope, but in terms of magical massive power gains i don't see it happening at all
the safety or area under the curve or smooth-ness of it may be better across the rev range due to the added scope, but in terms of magical massive power gains i don't see it happening at all
a high duration/late closing inlet will only dump compression (via reversion) at low rpm,s tho eh, and as the airspeed in the inlet gathers pace the dynamic c/r (and v/e) will rise bigtime :surrender:
my flat-top pistons protrude out the top of the block by 1mm, and my current 12+:1 engine pinks it tits off when the powerband starts lol (even with super unleaded
)
a high duration/late closing inlet will only dump compression (via reversion) at low rpm,s tho eh, and as the airspeed in the inlet gathers pace the dynamic c/r (and v/e) will rise bigtime
You make a good point, although my understanding was that the dynamic compresison ratio itself doesnt change, so although the cylinder pressures will vary under different load and throttle position the dynamic C/R will remain constant.
Are you saying that the cylinder pressures are going to get too high at high RPM becuase of the 14:1 static CR even with the reasonable dynamic CR?