Why is retune needed for JLT High Boost?

I would like to know why a tune is needed after installing a jlt high boost intake.

Depending on what CAI you are coming from... the 12" JLT has so much less restriction and so much more CFM that a lean out is a very real possibility.

Normally the MAF reads the additional air and the PCM requests the additional fuel... but the adaptive strategy can take several drive cycles... at least that's my understanding...

That can be potentially dangerous to tight pistons

It is far safer to get it right ASAP and let the adaptive strategy make minor little tweaks as it was intended.


Just MHO...

these engines are sensitive to the position the maf sensor is in. the jlt intakes move the sensor, so in order to get the maf transfer function right, you need a retune.

so will just staying out of boost help because i am installing a new clutch as well and i was going to get retuned and dynoed after the clutch break in period...is it safe to drive out of boost with that intake.

Keep it simple and wait to the put the High Boost JLT on until your finished with your clutch break in, then when you know for sure your going to have your car tuned put it on.

The high boost version puts the MAF right outside the t/b right? That leaves all the PCV air un-metered wich requires the lower end of the MAF transfer function to be re-tuned or else your STFT will be way off.

04CobraMatt said:

The high boost version puts the MAF right outside the t/b right?

YES... in the stock MAF location.



That leaves all the PCV air un-metered wich requires the lower end of the MAF transfer function to be re-tuned or else your STFT will be way off.
NO...There is a fitting that comes in the kit that you can put in the T body elbow to meter the PCV air.

Click to expand...

See pic...



You can drive it out of boost if you want... but these installs go better if you are not rushed.

Never seen it installed like that, thanks.

thanks for all the replies...will a bad TOB in my clutch affect DYNO numbers...because i might just put the intake on and take it to get dynoed before the clutch install.

Jimmysidecarr said:

See pic...

You can drive it out of boost if you want... but these installs go better if you are not rushed.

Click to expand...

That's what I want. It looks real nice Jimmy. :beer:
Was it any easier to install like that?

This is some good info i just bought a high boost and just by reading this my answer of a retune has been answered..thanks

SnakeBit said:

That's what I want. It looks real nice Jimmy. :beer:
Was it any easier to install like that?

Click to expand...

I'm not sure you want to use the word "easy" when talking about this install...LOL!!

But yes and even more so if you are running the JLT PCV Prefilters.
Notice I put a generous loop in my line to take the tension off the top grommet? I did something similar on the drivers side after my PVC pulled the grommet out... except I used a steel line and hose combo on that side.

I did not feel like this was a very tough install at all.... but apparently it has kicked a lot of guys in the A$$!!!

Taking your time and not being pressured to be done in XX hours makes all the difference in the world.... and a reasonable amount of mechanical ability.

I'm just a parts guy and the only mods I have not done myself are welding SFCs, setting up the ring and pinion after a TrueTrac switch.... and The Canton road race oil pan.(mod list link in sig)


So take that for what it's worth... for a reference point.


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