To boost or not to boost??

Had a compression test and leak down test today as a pre-clearance for a TRD supercharger on my 2015 Trd Sport. It has 100k miles. Wondering what people’s thoughts are on the results, and whether you think it’s healthy enough to boost it. This is a daily and I’d like it to last a while.

I tried searching tw for answers but couldn't find any definitive answers. I won’t say what the mech told me so as to not skew any answers.

compression/leak:
C1 - 190 / 12.2%
C2 - 195 / 10%
C3 - 202 / 8%
C4 - 209 / 5%
C5 - 208 / 6%
C6 - 209 / 8%

Let me know what y’all think!

 

Compression is only one factor of many. Bearing health is the biggest concern in my books. But the supercharger is fairly mild and hasnt blown up any engines in recent memory.

I say go for it, do your homework here.

https://www.tacomaworld.com/threads/trd-magnuson-4-0-supercharger-tips-tricks-and-mods.518932/

You must be at sea level. I'm about 1000ft and we get about 160 psi on 4.0's lol.

 

After owning my 06 for 9 years and just hitting 200k with a blown head gasket, I ended up getting new heads. After I said screw it Im stuck with this thing for a long time now I put a blower on it. Am kicking myself for not doing it sooner it is a blast dude it is so much fun now lol

 

Toyota says 189 psi or more, with a minimum of 145 psi.
But as Bishop said, the bearings are more important. As is the actual overall shape of the engine.
The 4.0 seems to be a robust engine. Like many Toyota engines, under powered and over built.
Aside from the early head gasket issues, they seem to hold up well.

 

Yea everyone says they are the best and to do it. I’ve read the SC mega but didn’t see anything on this. I’m hesitant bcz the mech said he wouldn’t given the leak - although he was very risk adverse, giving me a liability disclaimer prior to testing.

No one thinks the 12.2% leak is an issue? Is there a way to check the bearings. I’d like to think the engine is healthy, idles beautifully, doesn’t burn oil, feels and sounds good when WOT, but I don’t want to pour any salt on her wounds if she has them. Appreciate the feedback!

 

12.2 % is fair margin of error. You can try to isolate it.

I'd suspect carbon on an intake valve, but the leak down test is the only way to tell.

Remember, low compression is actually EASIER on an engine.

 

Hmm, he said something about feeling the leak with his hand over the oil cap? Not sure what that means.

and yea I guess that’s true. So I guess the consensus here is to boost it lol.

 

Do the cam gears before since you'll have easier access

 

I just put in the sc and love it (2014 with almost 90k miles). Especially for towing. I did not do any compression testing beforehand. I do plan to run a black stone oil analysis on my next oil change. This should give an idea about the bearing health without tearing the engine apart

 

Those are already in! Guess I’ll have to take off the spacer.

 

Same. Tried to keep my truck N/A for the past 7 years because these trucks are supposedly so reliable. At around 130k miles, found leaky head gaskets so I said "f**k it", had it fixed and supercharged it. NO REGRETS!!! Got it retuned with OTT and it is making even more power now at 287whp & 324lb/ft tq. Still on stock 3" pulley.

 

The more positive stories I hear the more I also find myself in the fk it mindset.

order a black stone kit today so we will see what they have to say.

 

You will always get all your money back from upgrading,Tacomas never lose value and with a Supercharger your truck will be worth upwards of $90,000 easily.