FIXED 469hp/600tq: (boost leak)YSi numbers low on Stock L99 with Holley Mid-Ram

[Unreal]

Pull restrictor and see what it does. No reason you can't make 700rwhp.

[RaiderSS]

Originally Posted by Slowhawk

You can't really do 7psi with a YSI. It will make nothing in the midrange. The blower is made to spin 14psi on a stock motor minimum.

Pulley it for more boost.

That's what tuner told me.... Makes sense and he is a proven and reputable tuner

"Let's do the Math

Stock auto 345-60 RWHP tops
Add a converter which will cost Dyno numbers and that Holley mid-rise intake -40-50 rwhp

Leaves you at 310-15 add 7 lbs of very very inefficient boost 420 rwhp should be expected. You will get 20 rwhp per lb of boost if it runs at a normally efficiency level. 10 psi is 200rwhp and so on.

Let's pull the charge pipe and then I can show how much your engine makes.

I have never ever seen a YSI on a stock L99 or even a stock LS3 for that matter. I'm talking STOCK no heads no cam no baby pulley ect....If it worked that's how they would sell it trust me.

They simply don't move enough air at low RPMs. No midrange

You need port velocity"

[RaiderSS]

Originally Posted by Nitroman28

Put a smaller pulley on it and wastgate to control boost. Spin it close to it's max rpm and set the wastegate at 12psi.

I may go this route replacing the cold or hot side 50mm blowoff... but he wants to pull the charge tube and install a speed density tune for NA with the throttle body open to the wind to see exactly what the motor is doing to see if I have a bigger issue...

The MAF is no longer used in the tune and the bend at the TB coupler isn't enough to cause this.

Thanks for the suggestions!

[RaiderSS]

Originally Posted by Unreal

Pull restrictor and see what it does. No reason you can't make 700rwhp.

Would he need to adjust speed density tune if I removed restrictor?

[Unreal]

YEs, tune would need to be adjusted, as boost will go up and it hasn't been tuned at higher boost.

FYI, AGP made 680-700rwhp on a few stock L99 motors, valve covers and TB never off, just 11-12psi, and one of those cars had a converter. Only reason they didn't go higher was stock tranny doesn't like more than that. Not saying goto turbos, just pointing out a stock l99 can make a solid 650+hp without issues. <500 is just sad.

So turn it up to 13-14psi, make ~700hp and be happy.

[376LS3]

Why would you run speed density? Id have another tuner look at the tune before giving up on a MAF tune. The car is going to run like crap outside of the weather it was tuned in. These MAFs can be scaled to run boost with no issue. Id get rid of the Holly and go back to stock intake.

[sick13ss1le]

regap your spark plugs i know it sounds like something small but i did it and gained 86hp on the dyno....just a thought

[Nitroman28]

Originally Posted by RaiderSS

That's what tuner told me.... Makes sense and he is a proven and reputable tuner

"Let's do the Math

Stock auto 345-60 RWHP tops
Add a converter which will cost Dyno numbers and that Holley mid-rise intake -40-50 rwhp

Leaves you at 310-15 add 7 lbs of very very inefficient boost 420 rwhp should be expected. You will get 20 rwhp per lb of boost if it runs at a normally efficiency level. 10 psi is 200rwhp and so on.

Let's pull the charge pipe and then I can show how much your engine makes.

I have never ever seen a YSI on a stock L99 or even a stock LS3 for that matter. I'm talking STOCK no heads no cam no baby pulley ect....If it worked that's how they would sell it trust me.

They simply don't move enough air at low RPMs. No midrange

You need port velocity"

I made those numbers with Cam/Lt/CAI/ TCI 4000 stall unlocked with a L99. If everything with the tune is right you need to spin it faster. I put a F1A on mine and spinning the blower Max rpm with a wategate set at 14lb. Not had it tuned or on a dyno yet. Should get it tuned next week. We will be doing a speed density tune. Waiting on a new meth pump.

[Nitroman28]

And I would put the stock manifold back on and see what it does.

[Pro Stock John]

Stock L99 cam, lifters and valvesprings?

In my opinion, your combo is flawed. I've had a YSI + 348 CID LS1 back in the day, but that's not even why I'm saying this (680rwhp, TH400, 9.4@144, 18 psi, 8:1, 5.9@116 1/8th).

~Your combo needs better valve springs, your power band is moved up, and you will or are maybe floating valves. Power might be taking a nose because of that.
~Your combo needs better lifters.
~You could cam it to manage your power band.
~I don't like your intake. That intake moves the power band up. You don't have the right lifters and valvesprings to complement that power band.

Good luck.

[Pro Stock John]

And like Don said, that YSI isn't designed to make 7 lbs of boost, more like 12-15 and they make as much as 25-27 in max applications. Keep in mind maxed out that blower is used for mid 8 second cars.

[RaiderSS]

Originally Posted by sick13ss1le

regap your spark plugs i know it sounds like something small but i did it and gained 86hp on the dyno....just a thought

They are new plugs, the oem ZR1 plug gapped to .038...

Not getting any misfires but what did you gap yours to?

[RaiderSS]

Originally Posted by Pro Stock John

Stock L99 cam, lifters and valvesprings?

In my opinion, your combo is flawed. I've had a YSI + 348 CID LS1 back in the day, but that's not even why I'm saying this (680rwhp, TH400, 9.4@144, 18 psi, 8:1, 5.9@116 1/8th).

~Your combo needs better valve springs, your power band is moved up, and you will or are maybe floating valves. Power might be taking a nose because of that.
~Your combo needs better lifters.
~You could cam it to manage your power band.
~I don't like your intake. That intake moves the power band up. You don't have the right lifters and valvesprings to complement that power band.

Good luck.

I was aware of all these things with the plan keep it turned down till i do cam heads by mid summer but i was still expecting mid 500's

I did find a loose vacum hose tonight, fixed it and will test tomorrow.

My current plan of action is N/A dyno to find out motor health. Then pulley back down to get the head spinning faster and try a waste gate at 9lbs...

[grocerygetter]

Just curious...why did you buy a ysi kit vs a 1500? Ecs stock 1500 kit should make 10 psi on your combo. Or close.