3Bar Boost on a 4A - can it be done?

[roadsailing]

yeah, no matter how many turbos or supers you have pushing you will end up with X pressure in the combustion chambers, so would be a good guide.

[oldcorollas]

i meant this thread..

http://toymods.net/forums/showthread...t=sleeve+block

[Jayem]

What is your compression ratio going to be? I recommend quite low. In my setup I have 8:1 and i think it could be lower since the grunt at low revs doesnt seem to be a problem. There's plenty of torque to put wheels spin at any speed or revs. Tires aint the best, I know.

My setup is
AirFilter -> Garrett T4 60/65-> Throttle ->Eaton M90 -> Intercooler -> 1G-GZTE

Setup isnt dynoed yet. So i cant really tell you about torque curves or about power. But both factors seems to be present while giving some Adidas to pedal.
Turbo starts to boost quite neutrally at 4000rpm or so. When I jammed Eatons bypass open and went for a test drive boost limit went like 2000rpms upper.
I have driven few hundred km's so far. No problems so far with the twin charger setup. Rev limiter is now at 8000rpm and boost is set to 1.6bar.
It's freaking winter now. So this off the road now and will go to dyno soon.

Few (not the most present) pics:
kkjhfd
hgfhh
fdasds
fgfdh
hgfhgh
dfsdf
Thats me! lol

Shoot with the questions if you got some...

[Cameron_Datto]

I been using a Factory standard internally 4agze bigport at 30psi in Twincharged format for 5 yrs without any dramas ,, I havent had the head even off it , so it has the factory head gasket still . it had done around 100000 kms as i bought it as a import engine . i have the engine in a race car so it is most likely I have only done 2000km in five years as the car only dose 1 km runs on the track at a time . it is making 300rwhp around 6800rpm with a very flat torque curve , it makes a max 15psi @ 2000rpm so it has a very grunty lower rpm power band .

[30psi 4agte]

/\/\/\ Are you talking in atmospheric pressure at the start of your post ..... IE the 30psi and then later on you say it reaches max 15psi at @ 2000 rpm ..Which i would assume is MAP.


Anyhow 45psi MAP in the engine would be something thats for sure ! Weather or not the block will take it is another story and one i cant answer.

The weakness in the 4a block is its bore arrangement.... You could run 45psi with no probs all day every day but then again you could split the bore straight up. Its almost like a luck of the draw thing. I have heard of bores splitting running less boost than what i run but i havent yet split one. ( touch wood ! ) Give me time and i might add that one to my list of distruction



Im still waiting to here from my mate from vegas about how he goes with those sleeves he put in ( http://toymods.net/forums/showthread...t=sleeve+block ) and weather or not he has the problems that we talked about...

[MWP]

Is anyone else also thinking that TB *before* an intercooler is a bad idea???
Surely that'll kill throttle response.

[Cameron_Datto]

[QUOTE=30psi 4agte]/\/\/\ Are you talking in atmospheric pressure at the start of your post ..... IE the 30psi and then later on you say it reaches max 15psi at @ 2000 rpm ..Which i would assume is MAP.


@2000rpm the max boost i can get is 15 psi and builds boost to 30psi at around 3000rpm , Just trying to give you a idea on how the twin charged makes its boost in the rpm band ,, All pressures are in Atmospheric Pressure (Gauge pressure ) , Not absolute pressure

[IN 05 NT]

What is your compression ratio going to be? I recommend quite low. In my setup I have 8:1 and i think it could be lower since the grunt at low revs doesnt seem to be a problem. There's plenty of torque to put wheels spin at any speed or revs. Tires aint the best, I know.

My setup is
AirFilter -> Garrett T4 60/65-> Throttle ->Eaton M90 -> Intercooler -> 1G-GZTE

Setup isnt dynoed yet. So i cant really tell you about torque curves or about power. But both factors seems to be present while giving some Adidas to pedal.
Turbo starts to boost quite neutrally at 4000rpm or so. When I jammed Eatons bypass open and went for a test drive boost limit went like 2000rpms upper.
I have driven few hundred km's so far. No problems so far with the twin charger setup. Rev limiter is now at 8000rpm and boost is set to 1.6bar.
It's freaking winter now. So this off the road now and will go to dyno soon.

Few (not the most present) pics:
kkjhfd
hgfhh
fdasds
fgfdh
hgfhgh
dfsdf
Thats me! lol

Shoot with the questions if you got some...

WHY DONT YOU HAVE A MEMBER'S RIDES THREAD? thats nuts^^^^

[nick.parker]

Is anyone else also thinking that TB *before* an intercooler is a bad idea???
Surely that'll kill throttle response.

Well I have a couple of feet of 2.75" induction piping in my current SC14 setup. There's not really much problem. Drivability is great. At high airflows there is not any appreciable 'response delay'.



In all honesty the biggest issues are the throttle size and the idle control with such a large vinlet volume. I used a VNV6 60mm throttle, which is a little touchy on a 1600cc engine for optimum 'car park driving'. But its still ok. Like the cushioned ceramic clutch, just takes a little bit of getting used to but basically all drivable as normal. The mnost difficult issue so far has been that controlling the idle is a bitch, mainly handling the overrun to idle transition, due to the large volume. I have tried various fancy control loops (home brew software) to adjust the idle stepper position in such a way to get a nice 'settling down' to the idle speed when ovverrun fuel cut exits etc.

For this reason ONLY I have considered using a 20V head with it idle air setup / quad throttle throttles. My throttle cable would operate the quads. In addition I would add a second electronic throttle in front of the supercharger which would operate such that it closes when I close the quad throttle etc - an algorithm would determine that best place based on what I do with the quads. THis would mean I wouldn't need a MEGA bypass valve and have heaps of air rush noise when I lifted off that gas....

Nick

[Cameron_Datto]

Hey Nick ,
I ended up using a 2 stage throttle body with a small and large throttle body to give a more progressive throttle control , off idle which works great , Also with a few tricks with the ignition timming and decelleration fuel cut you can get your throttle repsonse to behave very nicely in the light load bands just off idle .. with out getting it to the surge when you back off .. What ECU are you using ? I am using a wolf V4 which you can adjust every 125 rpm which helps in fine tune of the idle stablisation , I have spent so so many hours on getting the idle stable and crisp below 2500rpm iam very happy with it ,

[nick.parker]

Hi Cameron,

The ECU is my own design (hardware and software); a 6 year project. Its been running my AW11 for a couple of years now with no major hiccups. I'll get a website back up and running soon with some info about it. The two stage throttle you are running sounds good. My idle is really stable - I have implemented spark advance idle speed stabilisation. The bit that is tricky is obtaining a nice transition to slow idle from overrun, without the revs dipping too low momentarily. i.e. pushing clutch in when engine speed is say 2500rpm, yet the idle you want is 1200rpm. Also the idle stepper motor sometimes seems to miss a step, so I might need an adaptive algorithm to 'fix' up the missing step, based on steady state idle speed and potentially even including manifold vacuum. The hard part with the ECU has been getting good/factory drivability. Its nearly there.

Cheers, Nick.

[Cameron_Datto]

Nick ,
what i found is the less igniton advance you got the easier it is to get it stable when you back off , So i used 10 deg After Top Dead Center (retarded) in the lightest load band the MAP sensor reads when you back off on the throttle , , This should Not be the same load band the Map sensor sees when it is at IDLE , But the next 1 below that load band (Higher Vac) , The load band which the map sensor reads at idle should not have any After Top Dead Centre Timming , So what happens is when you open throttle the igniton advances as normal , when when you back off on the throttle ,the Vacumm reads higher than the idle load band and starts retarding the timming very fast bepending on how much vacumm you have, . The factory mini Cooper S supercharged motor uses this timming set up and i have seen up to 17 deg After Top Dead Centre Retard when you back off through reading the ECU live ..
The other adjust ment which helped is the Deceleration fuel cut sensitivity , i have it set very sensitive so when you BACK OFF it cuts the fuel ,so the large volume of air after the closed throttle body dosent get any fuel added to it so you dont get a surge .and slows the engine rpm down faster .

So by using a 2 stage throttle body ,alot of Ignition retard on Deceleration and Deceleration Fuel cut , the throttle control is very good in the rpm band just off idle .

Btw the Throttle body is off a BMW318is , but i have seen the early Holden Camrias with a throttle body much the same as it .

Cheers Cameron

[oldcorollas]

Is anyone else also thinking that TB *before* an intercooler is a bad idea???
Surely that'll kill throttle response.

apart from the idle issues the (guys with actual experience ) mentioned, response should not be a problem with SC setup as it works different to turbo..

(mathematically here's why) say the SC is pumping 3L of air per engine cycle (ie 2:1 roughly), and you have maybe 3-4L of tube volume (1m at 2.75")...
so even if the tubes are totally empty (ie, complete vacuum), then 2 engine cycles (ie, 4revolutions) is enough tio fill them to max boost....
of course that is assuming the engine doesn't ingest any air, but you see what i mean..
if through the first 2 revolutions the air just fills the tubing to atmospheric (engine still "at idle") and then next 2 revs it ingests atmospheric air (ie, WOT on NA car), and then next 2 revs, it can take 1 bar boost... so 6 engine revolutions....

maybe it will take 8revolutions? 2 rev at 3000rpm is 0.04 seconds, 8 revs is 0.16 seconds... response should not be a problem...

[Jayem]

I used a VNV6 60mm throttle, which is a little touchy on a 1600cc engine for optimum 'car park driving'.

I have similar touchy feeling with the 65mm throttle I have. I thought that If it would bother me in the long run, I will make it to open progressively.

Is anyone else also thinking that TB *before* an intercooler is a bad idea???
Surely that'll kill throttle response.

My setup responses very well too. BTW many factory setups with SC and intercooler have TB before IC. For example Ford thunderbird...

[fixeruperer]

i use a 72 or 76 mm of a falcon only problem but you learn to work with it, is when your spinning your wheels and u have to regulate the throttle you have to only just move your foot the tinyest bit to get the revs to drop and having such a laggy turbo if you drop the revs to much you gota start all over again.
ive got it down packed now