Pure 850 with JB4

[IILuckySe7eNII]

Wondering if it is safe to tune a pure850 and catless downpipewith only jb4. I found what I think is a good deal, locally and would like to take advantage. I will eventually get an unlock/tune, but was wondering if this was safe in the meantime?

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[rottmore]

If you’re worried about safety, stay stock. If you’re ready to dive into modifications, then skip that stupid piggyback and get a Femto unlock for a smoother, more refined power delivery. You don’t want to trick your ECU. You want full, direct access to the tables for editing. The only external controller I would buy for the car is a Reflex+.

 

[jmikes]

It technically is safe assuming you're running a map 6 that's tuned for it. There have been JB4 pure800/850 builds that have more or less worked alright in the past.

That being said, nobody, not even Jesse, recommends running a hybrid/upgraded turbo on JB4; you really should get an unlock and find a quality mhd/bm3 tuner for it, as you're missing out on a lot of performance and smoothness.

If you're totally stuck to JB4 or refuse to get an unlock; see if Jesse can help you make a decent Map 6, but you'd enjoy the car and upgrade 10x more with a full unlock.

 

[razorlab]

IN BEForE SOMeONE CLaIMS tHEy tOonEd thE fAsTeSt puRe850 WITh JB4 WitH TWO CUp holDer CoveRS AnD AN orANge tabBy IN thE bAck. COME At ME brO if YOU thiNk yOU cAn DO BETtEr.

 

[ColonelAdama]

Nah, 850 is a pretty big turbo. Best to unlock here. Will run out of fueling quick.

 

[B58-VPR]

Nah, 850 is a pretty big turbo. Best to unlock here. Will run out of fueling quick.

Can’t you add fuel with the JB4 now?

 

[razorlab]

Can’t you add fuel with the JB4 now?

 

[ColonelAdama]

Can’t you add fuel with the JB4 now?

You can raise the fuel pressure which will lower trims but the car is always gonna target Lambda 1, which is too lean for big power.

 

[razorlab]

but the car is always gonna target Lambda 1, which is too lean for big power.

Not always, but enough that it's a dumb choice to not have fuel control.

 

[SavagePassenger]

I would say just get the deal if you're sure about going to the bigger turbo, but wait to swap it until you get unlocked. Might as well do it the right way

 

[ColonelAdama]

Not always, but enough that it's a dumb choice to not have fuel control.

If its dropping below Lambda 1 its because timing is taking a dump. At least S58s drop under 13 afr in higher gears on stock flash. not so on a b58

 

[razorlab]

If its dropping below Lambda 1 its because timing is taking a dump. At least S58s drop under 13 afr in higher gears on stock flash. not so on a b58

Incorrect. There are enrichment factors based on different factors. EGT, Temps, Time, Load, Component protection, etc

 

[maniac]

If its dropping below Lambda 1 its because timing is taking a dump. At least S58s drop under 13 afr in higher gears on stock flash. not so on a b58

They both have the same safety precautions. The s58 has more boost, more timing and load and rides the knock threshold a little closer than our donk in stock form. OUr b58 doesnt need enrichment as early if all factors ( fuel quality/ambient/elevation etc ) are the same.

When you tune though........better to err on the side of caution. I cant vouch for piggy back as I have never used one as I have always felt that a good custom tune can and will be safer if done well. If you are replacing the turbo with something larger I would strongly advise NOT to use a piggy back.

 

[ColonelAdama]

They both have the same safety precautions. The s58 has more boost, more timing and load and rides the knock threshold a little closer than our donk in stock form. OUr b58 doesnt need enrichment as early if all factors ( fuel quality/ambient/elevation etc ) are the same.

When you tune though........better to err on the side of caution. I cant vouch for piggy back as I have never used one as I have always felt that a good custom tune can and will be safer if done well. If you are replacing the turbo with something larger I would strongly advise NOT to use a piggy back.

Yup, all truth, but I find B58s actually run more timing on the factory flash.

 

[razorlab]

Yup, all truth, but I find B58s actually run more timing on the factory flash.

The setpoint tables between the two are actually very similar, however the S58 has different dynamic torque management tables based on wheel slip, etc that are more aggressive than the B58. The manicooler on the S58 is MUCH better than the B58 so IAT timing pull happens much much less. Even on tuned S58's running 28-29psi out the top, you can lap them for MUCH longer than a B58 at the same level, oem manifold vs oem manifold.

The knock threshold stuff that someone else stated is totally BS. For starters, the S58 is lower compression than the B58.

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