Safe Boost and AFR values- B58 tuning boxes

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Madasadad1
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Safe Boost and AFR values- B58 tuning boxes

Post by Madasadad1 » Wed Oct 02, 2019 2:32 pm

What would be considered safe Boost and AFR values when using a tuning box, which doesn't have the same level of control as a remap. Im concerned that high levels of boost may cause the engine (B58) to run lean in attempting to achieve the gains quoted by the manufacturer

Goon
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Re: Safe Boost and AFR values- B58 tuning boxes

Post by Goon » Wed Oct 02, 2019 4:14 pm

I too would like to know this.

eddbluespark
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Re: Safe Boost and AFR values- B58 tuning boxes

Post by eddbluespark » Fri Oct 04, 2019 10:40 am

Madasadad1 wrote:
Wed Oct 02, 2019 2:32 pm
What would be considered safe Boost and AFR values when using a tuning box, which doesn't have the same level of control as a remap. Im concerned that high levels of boost may cause the engine (B58) to run lean in attempting to achieve the gains quoted by the manufacturer
What boost level is appropriate is a subjective question, and depends on how the particular tuning box specifically works.

Regarding running lean, the ECU targets AFR values live, so with most tuning boxes (including ours)the ECU continues to target the same AFR level and does not run any leaner than stock at any point in the rev range. Here is an example of our box with Stock AFR and Tuned AFR overlaid:

Image
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Sam_M
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Re: Safe Boost and AFR values- B58 tuning boxes

Post by Sam_M » Sat Oct 05, 2019 11:30 am

eddbluespark wrote:
Fri Oct 04, 2019 10:40 am
Image
Off topic but I’m surprised that 14.x is what’s being targeted under full load.

Based on my albeit limited dicking around with various 90s Japanese turbo motors I’d have expected mid 12s.

What are the engine tech advances that allow such a lean full load burn?

Is there power to be had with a richer target?
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Re: Safe Boost and AFR values- B58 tuning boxes

Post by Slooby » Sat Oct 05, 2019 10:09 pm

Running at around stoich isn't really that lean, plus notice how much richer things get at the top end on the remap?

It all depends how close to the edge you were running on the 90's stuff, what ecu (or aftermarket boost and fuel controller) you were using and whether they could support a wideband Lambda sensor...

Back in the day I initially ran a Possum Link ECU on my Impreza which was...ummm...basic. Had to run rich as hell on the stock choclate engine as it (the ecu) didn't even use the stock narrow band lambda, that was plumbed into a lambda link display. Still took a UK engine to 360 reliable brake with bolt ons.

Then we got serious and I built a forged 2.5 for for the car with a rotated Garrett GT30/40 set up, and the link was replaced with a Pectel T6 2000 ecu, now that could talk to a wideband lambda (trusty NTK L2H2) and we could go leaner because the ecu could pull timing/chuck in more fuel if it saw that the AFR targets weren't being met. That engine produced a lazy 500 of each on 1.5 bar boost with 95 ton fuel...it was a beast...ahhh the good old days...
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Sam_M
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Re: Safe Boost and AFR values- B58 tuning boxes

Post by Sam_M » Mon Oct 07, 2019 8:11 am

Slooby wrote:
Sat Oct 05, 2019 10:09 pm
Running at around stoich isn't really that lean, plus notice how much richer things get at the top end on the remap?
Yeah, just seems lean for max load, and that rich section is only the last 700rpm or so.
Slooby wrote:
Sat Oct 05, 2019 10:09 pm
It all depends how close to the edge you were running on the 90's stuff, what ecu (or aftermarket boost and fuel controller) you were using and whether they could support a wideband Lambda sensor...
Was a mixture, and all road cars

Daihatsu Charade GTxx running a Microtech(yuck) with wideband - was running 2.x bar of boost(basically free spooling the turbo, forged engine as standard!) with a hybrid turbo and lairy cams

MR2 Turbo Revision 3 - MAP based engine, intake, exhaust, ST205 chargecooler - Power FC, datalogit wideband running 16psi on the stock turbo with stock engine.

Mazda RX-7, pretty much stock except intake and intercooler, running an adaptronic with wideband running 12psi on the stock twins.
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eddbluespark
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Re: Safe Boost and AFR values- B58 tuning boxes

Post by eddbluespark » Mon Oct 07, 2019 10:05 am

Sam_M wrote:
Mon Oct 07, 2019 8:11 am
Yeah, just seems lean for max load
If it was an MR2 Turbo, or 2JZ or any other 90's Jap car it would be insanely lean for max load.

The thing is it isn't. The big differences are direct injection, wideband AFR and modern knock sensing.

Tons of ultra modern turbo engines are running stoich right to redline from the factory.
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Slooby
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Re: Safe Boost and AFR values- B58 tuning boxes

Post by Slooby » Mon Oct 07, 2019 1:45 pm

Are the Bxx engines running ion sensing coil packs (for individual cylinder knock sensing) like the BMW Motorad bikes are then?
2016 M140i 5 door Manual
2013 Triumph Street Triple R
1988 T25 1.6JX TD Camper
Projects: 1973 SIII 109" 2 1/4 Diesel, 1965 SIIA 88" 300Tdi Hybrid, 1968 MkII Mini 1000
Gone but not forgotten: E39 M5, 1998 Impreza 500 of each toy

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