Big boost what ratios are best

[RedDrifter]

Ok I am about to give my R32 RB20DET its final power tune.

The motor is in good health but is stilll stock.

My mods include-----> Blitz front mount, ITS turbo, RX7 pinktop 550cc injectors, 3" turbo back exaust. Z32 afm will be added before tune aswell.

I wish to run 20psi and I would like to know what ratios would be good for power but not too lean.

Atm I run 16-17 psi and am running 11.7 a/f and run 24 deg btdc from 6500 to 8000rpm.

If I winde another 3-4 psi (aka20psi) will I need to run a little richer to keep the exaust temps down or should I be ok at 11.7.

I would expect about 230-240 rwks at this level of boost.

Thanks guys.

[Roy]

Isnt 11.7 pretty rich to start with. Im throwing my thing on a dyno this saturday and im going to keep winding boost into it unitl the thing stops making power. Im hoping at 22psi it will make 265rwkws. Fingers crossed at 20psi it will make 250rwkws.

Before playing ill work out what A/F my thing runs when at 234rwkws, i dont know what they are but they are on the money...strong power, no pinging, great reliability and pretty good economy, (not when im booting it of course:()

At those boost levels i dont think the exhaust temps are as big an issue as the bottom end loads as a result of the revs and cylinder pressures...make sure you have a good grade oil in there and you have good oil pressure:)

What computer are you running? As long as you are keeping an eye on water, oil, inlet temps and fuel pressure it will be interesting to read about your results. Your about the first person i would have heard from with regards to results using an ITS turbo...any more details on it?

[RB power]

hey my rb20det makes 180rwkw on 9psi is this good?

what power do u guys make at 9psi?

[pnblight]

11.7 should be fine i run around 11.9 to just under 12 in my gtr at 20 psi at 530rwhp(397rwkw) and up 27 deg adv timing

[RedDrifter]

Isnt 11.7 pretty rich to start with. Im throwing my thing on a dyno this saturday and im going to keep winding boost into it unitl the thing stops making power. Im hoping at 22psi it will make 265rwkws. Fingers crossed at 20psi it will make 250rwkws.  

Before playing ill work out what A/F my thing runs when at 234rwkws, i dont know what they are but they are on the money...strong power, no pinging, great reliability and pretty good economy, (not when im booting it of course:()

At those boost levels i dont think the exhaust temps are as big an issue as the bottom end loads as a result of the revs and cylinder pressures...make sure you have a good grade oil in there and you have good oil pressure:)

What computer are you running? As long as you are keeping an eye on water, oil, inlet temps and fuel pressure it will be interesting to read about your results. Your about the first person i would have heard from with regards to results using an ITS turbo...any more details on it?

The oil I use is penziol 5w50 fully synthetic and it seems to be pretty good.

My ecu is the stock ecu that I have recalibrated and remapped to suit the new injectors and my new turbo. Its tunned great for up to 16psi but it pings very slightly if I go any higher atm.

Just running a little two much timing at that point which I will rectify on the weekend.

I do like to try new things and be different so I chose the ITS turbo (Pic in my Avatar)

It seems to be a very good turbo but I think it was more designed for the RB25 though.

Do you think running 12:1 at 20/22 psi would be ok?

What is the max power level the RB20 will take reliably?

Once tuned I will let you all know how it goes.

[RedDrifter]

11.7 should be fine i run around 11.9 to just under 12 in my gtr at 20 psi at 530rwhp(397rwkw) and up 27 deg adv timing

Nice!!

I might bump the rartio up to 11.9:1/12:1 then.

[Roy]

Do you think running 12:1 at 20/22 psi would be ok?

What is the max power level the RB20 will take reliably?

 

I dont know about just jumpin gin and running 22psi, i woudl suggest baby steps. I have never run that sort of boost, and i dont personally know anyone that has with a std RB20...so whilst ppl may have done it, and it could b perfectly safe, if your being a pioneer then best take it slowly:)

The ITS turbos are based on Garrets so if the the thing feels a bit big you can always just go and grab a smaller housing, cant you?

As for the power they can reliably make...lol, who knows. My thinking from an old thread...

http://www.skylinesaustralia.com/forums/sh...&highlight=RB20

Have a read of these few threads and you will get a feel that most ppl seem to think that 220rwkws is the safe, reliable limit....me i think (more hoping) they can take a bit more:)

http://www.skylinesaustralia.com/forums/sh...&highlight=RB20

http://www.skylinesaustralia.com/forums/sh...&highlight=RB20

http://www.skylinesaustralia.com/forums/sh...&highlight=RB20

[RedDrifter]

I dont know about just jumpin gin and running 22psi, i woudl suggest baby steps. I have never run that sort of boost, and i dont personally know anyone that has with a std RB20...so whilst ppl may have done it, and it could b perfectly safe, if your being a pioneer then best take it slowly:)

The ITS turbos are based on Garrets so if the the thing feels a bit big you can always just go and grab a smaller housing, cant you?

As for the power they can reliably make...lol, who knows. My thinking from an old thread...

http://www.skylinesaustralia.com/forums/sh...&highlight=RB20

Have a read of these few threads and you will get a feel that most ppl seem to think that 220rwkws is the safe, reliable limit....me i think (more hoping) they can take a bit more:)

http://www.skylinesaustralia.com/forums/sh...&highlight=RB20

http://www.skylinesaustralia.com/forums/sh...&highlight=RB20

http://www.skylinesaustralia.com/forums/sh...&highlight=RB20

The a/r on the rear housing is .48 and I till dont get one bar till 6 grand.

Hey thanx for the links I will have a squiz right now.

[RedDrifter]

OK I have done some thought.

If I run a slightly richer a/f of say 11.7 (what I am now) the temp of the exaust gases will stay fairly stable. If this is the case I would expect I could run a decent amount of ignition advance.

Obviously to much and it pings and then the temps raise right?

So if I set my knock map on my ecu to run say 3 degrees lower than the main map if it does ping the ecu will switch to that map. (It does. Tetsed a few times from boost spikes while setting up bc)3 degrees would /should avoid knock then I guess. Conzult also spits out a knock code when this happens even when I didn't Hear any knock. Gotta love knock sensors. :inlove:

If this works as i should I could have a very reliable motor at high power levels.

As long as something out of bad luck doesn't go wrong of course.

The motor was bouht from a forum member and he didn't have it boosted too much at all from what he told me.

He did the water pump and a new cam belt within 5000kms of selling it to me.

I had a leak down test done and it had less than 5% leakage at all six pots.

So its fairly happy I guess?

If the Rb20 is over filled with oil a bit this should help things too. Don't seem to get any extra blowby and I cant see why this wouldn't help to avoid oil starvation?

Also if teh engine is kept from knock surely i could take a fair bit of power? 250rwkws?

Sorry about rambleing on.

I just got adsl going tonight and I am a little keyboard happy.

[Roy]

1bar at 6,000rpm, damn is it a 700hp turbo? What size/spec turbine does it have? With the asize A/R housing you are running it must be a huge turbine.

Is the exhaust/intake or free'd up?

[Cubes]

Richer AFR's reduce the exhast gas temps.

Advance the ign. timing and it reduces exhaust gas temps.

Retard ign. timing and it increases exhaust gas temps.

My thoughts would be a stock piston motor really wants to be kept as far away from detonation as possible. Detonation occures easier with high EGT's.

I would 'think' run it richer, this will allow you to advance the ign. timing.

Richer + more advanced ign. timing = a cooler EGT.

This could be the reason drifto's tune this way in Japan.

From memory they use low to mid 11 AFR's, depending on power level.

[RedDrifter]

1bar at 6,000rpm, damn is it a 700hp turbo? What size/spec turbine does it have?  With the asize A/R housing you are running it must be a huge turbine.  

Is the exhaust/intake or free'd up?

Exaust could be a little bigger I guess. 80mm atm primary muffler too.

As for intake its not all that freed up either.

Need to get some pipework done soon.

[RedDrifter]

Richer AFR's reduce the exhast gas temps.

Advance the ign. timing and it reduces exhaust gas temps.

Retard ign. timing and it increases exhaust gas temps.

My thoughts would be a stock piston motor really wants to be kept as far away from detonation as possible. Detonation occures easier with high EGT's.

I would 'think' run it richer, this will allow you to advance the ign. timing.

Richer + more advanced ign. timing = a cooler EGT.

This could be the reason drifto's tune this way in Japan.

From memory they use low to mid 11 AFR's, depending on power level.

Thanx for the advice mate.

Dunno what I will do yet though.

[Packy]

Reddrifter: Once ya get it all done, tell me, we'll have a race

Have you put it on the dyno yet, or are you still road tuning??

[RedDrifter]

Reddrifter: Once ya get it all done, tell me, we'll have a race

Have you put it on the dyno yet, or are you still road tuning??

Still road tuning but I will have it on the dyno next week at the Ingham car show.

After that I will probs get it on a dyno again to just teak the maps a bit.

[RedDrifter]

Well I am fairly happy with the dyno result from the Ingham car show.

299.99rwhp @16-17 psi running a 11.8 afr.

I didn't have the boost controller set up for 20 psi at the time but I am really happy with the result. Few of the V8 boys were startled buy that.

I dont have a dyno graph yet but I will be talking to TMS sometime this week to try and get a run on the dyno (one used in car show) at 20psi some time.

[jazza08]

Im just abit confused ere.. ur car doesnt hit 1 bar until 6,000rpm, so the turbos obviously huge but ur only making 300rwhp on that high of boost??

A gt25/30 will hit full boost at 4,000rpm and make the same power on lower boost levels??

What made you go for that turbo, my mate has a car that hits full boost at 5.5k but makes 360rwhp on 20psi.. wud of though if ur turbos that big ud make alot more power?

[RedDrifter]

Im just abit confused ere.. ur car doesnt hit 1 bar until 6,000rpm, so the turbos obviously huge but ur only making 300rwhp on that high of boost??

A gt25/30 will hit full boost at 4,000rpm and make the same power on lower boost levels??

What made you go for that turbo, my mate has a car that hits full boost at 5.5k but makes 360rwhp on 20psi.. wud of though if ur turbos that big ud make alot more power?

Geeze give me a break man. I haven't had a lot of time to do this and I'm sure I could get more power out of it yet.

Got to remeber its not a ball bearing turbo either.

As for why I went with this turbo?

Decided to try something different and not follow the sheep.

[jazza08]

Didnt mean to sound like i was having a go!!

Just a few things i was confused about thats all

[Cubes]

Some times following the sheep prevent dissapointments and what if's.