• Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

Sprintex Supercharger hits 12 pounds Boost!!

Just saying, to be accurate, it is a gasoline+meth mixture going thru the port. Due to the complete mixing thru the S/C, I can't say one or the other. Maybe I will check the other jeep which just has gas via the 7th inj thru the S/C and no meth and see what that port looks like.
 
To clarify my current setup, 4.0L, Sprintex 210 supercharger, 3" cowl CAI, 70mm TB, ported sprintex S/C intake manifold, 1.7 Yella Terra roller rockers, Gibson headers and 2.5" cat back exhaust, with 7th injector and meth/washer fluid injection, 54mm S/C pulley and ATI balancer. At near sea level, system makes 12 pounds boost and even spiked to 12.5 pounds on a cold night. Yes at 12.5 pounds boost it popped a head gasket on the 165K miles engine.
 
Yeah, thought it was drained when pulling the hoses and they were dry. It did help check for piston cracks/leaks, LOL.
 
Broken spark plug tip. No blockages, all drained out.
 
Yeah, thought it was drained when pulling the hoses and they were dry. It did help check for piston cracks/leaks, LOL.

mmmcoolant.jpg


Damn, that is an impressive amount of coolant trapped in the head. Could the blocked coolant passages have held it in the head?
 
Stock 160K miles head gasket.
 
Having bit of pre-det there? Also why are all of the cooling passages pluged?
Cylinder #6 ate a sparkplug. No detonation.

Didn't drain the coolant before removing the head thought there was less coolant in the engine. No biggie. Stock head gasket coolant passages were gunky though (if that's what you're referring to..)
#becauseracejeep!
Wrong Jeep. Lol.
 
Last edited:
Cylinder #6 ate a sparkplug. No detonation.
spark-plug-condition-colour-640x266.jpg

Survey says, pre-ignition/detonation caused the plug damage, due to lean mixture. Also detonation increases cylinder pressure and will blow the HG as seen in your pictures.

Another fun fact, reduced coolant flow through the head will cause combustion temps to rise leading to detonation.
 
Last edited:
Bought new sparkplugs from Pepboys several months ago. Was given stock heat range plugs. WHOOPS!!

My Jeep is tuned rich. Didn't detonate.
tumblr_ly4wxiPIJn1r5ttulo1_400.gif

Are you even reading what you are typing?:compwork:

Mild detonation can occur in almost any engine and will not cause damage. Prolonged heavy detonation can crack pistons and rings, blow out head gaskets, damage spark plugs and valves, and flatten rod bearings.
Source - http://www.onestopauto.com/What-causes-spark-knock.html
 
Last edited:
Thanks, no detonation.
 
OK, or maybe just a 160,000 mile engine, original head gasket and head bolts and too much boost, 12.5 pounds and lifted the head, and wrong heat range spark plugs. There are other causes of head gasket failure other than detonation. But thanks for the heads up, we will look closely for signs of detonation when we restart.

We are going back to the larger pulley and 8-8.5 pounds boost b/c the better flowing head should fill the cylinders better and increase cylinder pressures. Might even see a drop in boost but more HP/TQ with the better flowing head. Time and dyno will tell.
 
Properly tuned ignition means that you do not have to run rich to prevent detonation. The ignition rule of thumb is to retard the spark "one degree per pound of boost" but that is only a starting point. The actual timing must be correct or blown plugs and/or head gaskets will occur.

Only a matter of time...

It took me a bit of time, with a knock sensor installed, to get the timing dialed in on my Sprintex installation. Now that it is correct, the sensor has been removed as it is no longer needed...

Running rich just, IMO, hides issues. Better to correct the issues than to bury them with excessive fuel.

That is My Opinion. Feel free to disagree.

Even if you can not hear the detonations, it does not mean they are not happening. It is a well documented fact that by the time you can actually hear them it is way too late...

That is not an Opinion, it is a Fact.
 
Back
Top