A couple of things... If the number in row two, "Maks. moc [KM]" is actually KW/kilowatts then things are definitely strange. If this is the case then your NA LS2 put out 524 hp which is a LOT for an NA LS2 (too much to be very credible). The FI LS2 setup put out 490 hp (not unusual for a mildly boosted LS2). Also converting the NM values over to lbs/ft gives you 370 for the NA and 357 for the FI. 357 lbs/ft is waaaaay low for the FI version. As David said it could be valve float but you start seeing it as early as 2000 rpm. That is is pretty soon with boost this low. With all of these peculiarities I would definitely be tearing down the engine (at least the top end) to see what was wrong (multiple broken springs would be my guess).

To your original question, the LS9 cam is hard to beat for a mildly boosted engine. The cost of $125 versus around $500 for a custom grind is IMO too tough to overcome.

 

If your IATs are what you say, that is not the issue for sure. Glad to hear you have the intercooler & heat exchanger ( little radiator).

Forgive me if this sounds stupid ( maybe its the language barrier). The Dyno graph that I'm looking at seems to me to be in order. The top of the sheet ( seems to me) Representative of TQ & HP ( together on the same run). They are exactly as a PD blower should look. The Blue & Yellow go together as the same run. The lower 1/2 of the graph is your NA run. That run has the characteristics of a NA motor while the top is a mirror of almost every maggie sheet Ive ever seen. No ?
If this is the case you seem to have a little belt slip as evidence by the TQ line being wavy.
Maybe someone can help here as Im horrible at the conversions that were mentioned above. However, this scenario makes more sense.

This may as simple as misreading the results & a very fixable belt slip.
What do you think ?
There are a few easy steps to get more boost out of this as well.

Have you driven the vehicle ? You should be able to feel a dramatic difference if my hypothesis is correct. Lower RPM will put you in your seat .... nothing like your NA setup.

 

I sort of discredited, or at least forgot, that your boost was coming from a belt... belt slip will definitely explain the choppy dyno results, which I originally thought may be due to valve float.

Both are still a distinct possibility, but it is probably belt slip. If you had broken valve springs, I wouldn't imagine that the car would be drivable.

 

In Polish language KM means HP ( horsepower ). Nm is an unit of torque.

Yellow lines are from NA engine, the blue lines are from charged engine.

I forgot that the problem might be a slipping belt because my tuner said that the boost pressure is continuously 0.3 bar, none of losses. This is the prove for not slipping belt, am I right ?

I am completing an order from USA to Poland, the LS9 cam will came to my list, what You think what should I order to strengthen my engine and give it the power back ? Some springs (which ) ? Something more ? Maybe I should install some additional belt tensioner ??

 

The engine doesn't need any additional strengthening. It will handle everything that blower can throw at it perfectly fine in stock form.

Valve springs! Buy some pac1218's, at a minimum.

If boost was consistent, then you likely are not experiencing belt slip. But if there's a better belt tensioner available for that blower, then it definitely won't hurt anything.

I think the ls9 cam will serve you very well. And you can probably find other people on this forum who have a really similar combination, you might want to get a copy of one of their tunes, and either upload it to your car or at least compare it to your tune.

You could start a thread in the tuning section asking for anyone with ls2/maggie/ls9 cam tunes.

 

everything said above... agree.

beside the cam ......
The easiest way to increase your power will be to increase your boost.
1. Heavy Duty belt tensioner is a must have item. I can recommend ECS
East Coast Superchargers. They have an option for LS2 made especially for PD blower use. The heavy spring tensioner will keep the belt in contact with the pulley as RPM increases.

2. we need to spin the blower faster, so replacing pulleys is the way to do this. Most people simply replace the upper pulley on the supercharger to a smaller one. This is the simplest way to go however, the smaller the pulley the less belt wrap and more likelihood of slippage. The HD tensioner should hold it as long as you don't go smaller than 2.9" upper pulley. Id rather go with the next two options instead.

A more intrusive way to accomplish the same thing is to replace the crank pulley with a larger one. An oversized 8" pulley to replace the stock 7.65". This is a bit more work but it will keep the pressure off the upper pulley & you should see a few more LBS boost.

Another method that will cost you zero money is to swap the pulleys on the rear of the blower. I cant see it from the pictures but you may very well have the older version which came stock with one pulley larger than the other (on the back side of the blower) get a mirror & try to read the embossed size. It may sat 3.0 or 2.7 etc.. The smaller is usually on the Jack Shaft & the larger on the blower side. If you take them off and switch it around you will effectively spin the blower faster and here again you did not compromise the upper (front) pulley which is prone to slip. The rear can handle the extra effort as they are an 8 rib config.

personally I would go with a larger crank pulley & swap the rear pulleys. In addition to the heavy duty tensioner.

Now, a word to the wise. If you go further down this road ( Ie: reduce the upper pulley less than 3" or so which is what you may have now) you will have IATs that go out of control along with belt slip. These maggies can only spin so fast and can only produce just so much boost before they are completely inefficient. My experience was exactly that & we chose to spray meth along with a very expensive 8 rib conversion to compensate.

With that said, ( along with the proper tune) it will make great reliable power with the conservative recipe above.

hope this helps.

 

You mean this tensioner??:

http://www.eastcoastsupercharging.co...belt+tensioner

Where is it mounted? In the place where original tensioner is ?

Can You give me some links with the bigger than original crank pulley, I can't find anything

My pulleys at the back of the blower are unfortunately the same picture:




Do You know what is my blower model and what should be it original boost ? ( the 0.3 bar is it standard boost ?? )


What You think, the LS9 CAM + PAC 1218 springs will be good connection ?

And last, what should be the power of my LS2 with all this stuff ??

 

Ok, .3bar is 4.35psi... The non-intercooled maggie ran ~5psi.

You said you have the intercooler, so yours should be up around 9psi, or .63bar.

A bone stock ls2 with an intercooled ~9psi SHOULD put 500+ horsepower to the wheels.

The ls9 cam with pac1218 springs is a tried and true combination. It should serve you well.

Hopefully your blower is in good condition, and this issue can be resolved by simply replacing a couple little parts (belt tensioner and crank pulley) versus having to rebuild the maggie.

Did those blowers come with lame injectors? I don't know what they came with, but I would imagine you probably want some 60's or even 80's in there.

 

Maybe that means that my charger is finished ? It gives only a half of its normal boost. Don't You think ?

Another possibility is that previous owner change some pulleys, I don't know.

Is there some other possibilities ?

How I can check condition of my maggie ?

I get the blower with some injectors from previous owner, but I don't know what are they really are... Do You know what are they should be ??

 

all correct however the boost is variable according to modifications to the motor. Ie: headers will create a better flowing motor & reduce boost. Are those headers or just wrapped manifolds?

Can you tell me what pulley size you have on the top ( jack shaft) ?

https://www.google.com/url?sa=t&rct=...07467506,d.eWE

Inovators West for pulleys

 

I must check this pulley size, i don't remember.

This is my manifolds ( when they were in production phase) , maybe it helps:




What You think ?

 

Very nice craftsmanship.
Yes, re: the tensioner that is the correct part. You can use your present 6 rib pulley. It will bolt up in the stock location & utilize some of the available threaded holes for extra support. This unit will keep slippage down to a reasonable limit.

There is something else that you should verify ( it may sound silly , but it happened to me). Verify that your throttle body is opening 100%. My cable was out of line & I once was opening only 80%. It made a big difference.

See pic attached. It a chart for pulley vs blower speed.
As you get into the red you will see less efficiency. Limit yourself to maximum recommender RPM and your blower will last.

Just from experience I can tell you that a built LS2 motor: heads, cam & exhaust may only see about 7 - 8 lbs on the top safe side. A good flowing motor will have less resistance ( boost). But that's a good thing. It's the power and curve not the amount of boost that is the goal.

 

Ok, I need to check my throttle, it is steered by wire.

Thanks for the pic, it definitely helps! It is correct for My maggy?

"Yellow speeds" are ok, or better stick to the green ?

What You think, in my case it is needed to use an 8 rib-conversion? Or it is the waste of money? I was think on this, because only crankshaft pulley is half of the price for whole 8-rib conversion set.

 

That blower looks like a 122. The 112 is not that big.
If you bought the unit used, there is no telling what injectors that you have. If you don't have the correct injector info in your tune, it will lose power and cause more problems. I would think that you need at least 42# injectors for 500+ horsepower. What is your injector % now at wide open throttle?
You didn't mention what computer that you are using for engine control. Nice setup though!
Innovators West makes a overdrive (8") crank pulley for the LS2. Be sure and get the crank pinning kit. Otherwise the pulley will turn on the crank snout.

 

I don't have the infos about my injector % now at wide open throttle. I must speak with the guy who made an ignition map.

My computer is ECUMASTER EMU, I do not know do you know this computer? This is Polish production.

 

I see your point re: pricing of the 8" vs the entire kit. For me it would be worth the money for the 8 rib kit. If you plan on keeping this system in place the 8 rib will be a great investment. Especially when you want to test the limits of the blower vs efficiency, you will at least be sure that the belt slip is not an issue.
Funny ,,,, I just now remembered that when I put the 8 rib system on .... My rear belt started to slip. That was a simple replacement.

Good point re: injectors ( I had 60lbs on mine). Also, huge point .... Upgrade your fuel system. At least the pump. These kits usually come with a booster from magnuson. I went with a #255 walborrow fuel pump. Very important.

Your low boost may very well be the product of a pulley system that is not able to spin this fast enough. Let's calculate the size of your upper pulley with the crank & get some facts on the table.

Another possible ( band aid) not a proper fix for a blower that is starting to wear out. Consider a water/ meth system. The extra cooling and fuel the meth provides is excellent but what I'm referring to is the effect of the liquid through the blowers. I don't know the technical term but what it does is fill on the microscopic gaps between the blower rotors. makes a good seal & makes boost.

 

Hi, i have checked my upper pulley size and it is 3,5" :O



My rear pulleys are both 3,2"

What You think ? I need to replace it for what size?

My full pump is bosch 044, and i think that is good enough.

 

Has anyone verified that the bypass valve is adjusted properly, and that your not bleeding off boost? I like to start with the most simple thing first.

 

Now this makes a little sense to me.
The 3.5" pulley is very conservative. I can see how 5lbs works be hard to see.
My system came stock with:
1:1 rears ( which is what you have)
3.1 upper on a stock crank pulley.
I made at least 7 - 7.5 lbs on a good flowing motor ( heads, cam & exhaust ).

Get the HD tensioner & 3.1 or even 3" pulley. You should be right on spot re: belt slip & you will make plenty of boost which will translate into power.
For you & the drifting .... This will be instant & violent torque !

You are presently spinning that blower at a very low rate of speed. Probably 13,000 RPM. With a 3.1 you will be in the low 15k range. That will add a few pounds of boost for sure and plenty of additional HP/TQ. That will make the difference. This is probably an easy fix.

Do check the bypass for leaks as well.
Be sure you are getting sufficient air flow through the filter as well. This beast needs to breath on both sides. I'm sure you have a free flowing K&N style filter so probably not an issue.

 

Thanks for informations, I'll do.

I want to install the ls9 cam and strong springs in the winter. Tell me, is it good idea to do it without removing cylinder heads ? Or better to take them of, and put some racing cylinder gaskets and some ARP bolts for cylinder heads ?