Looking for LSA build advice

[LaN-]

For many years I've been trying to get this fat pig moving and I've finally pulled the trigger on a blower. Over the winter I'll be adding an LSA and I'm looking for some advice on the overall build. My goal is more torque to combat the weight of the gen5+convertible and I'm concern that some of my NA mods may push the total power figures beyond the "safe" / "practical" level and I should scale back in some areas.

2014 SS M6 Convertible

::Current Mods::
- Intake
- Long tubes + NPP
- 3.91 Rear gear
- Cam (227/239 on 114+4)
- Ported heads
- Under drive pulley
- Full suspension upgrade (basically every product bmr sells)

Questions

1.) Should i swap the 3.91 back to the stock 3.45, or will some 305/315 radials and my suspension upgrades be enough?

2.) Is switching the rear gear a bandaid and upgrading to a truetrac a better solution?

3.) I don't know much about cams so I'm not sure if this cam will work well with the LSA. If it does will I be in a situation where I'm making more power than is considered "safe"?

4.) Since I'm tearing things down (assuming i should swap the cam) are the ported heads with my current cam (or new) going to push the power limits and I should consider selling them for a stock pair?

TLDR
If I throw a LSA blower onto my exist setup will I be setting myself up for a spin fest, a blown block or arrest me power?

Thanks for any input!

[dreksnot]

An LSA will not put you in to crazy power and your current mods won’t need changed. 125 more HP will help accelerate the convertible but you’re not going to be terrorizing the streets and sidewalks with it.

[JMI]

We did 740rwhp and 672rwtq with my buddy's CTS-V earlier this week with the 6L90 transmission. Stock bottom end on E85 and only 13psi of boost. But we put a lot of money on the heads(custom AFR),fully ported blower,NW102TB,big 4.5" intake with a cam & matching valvetrain.2" headers.

At that power level,Sticky tires will be needed regardless with the 3.91 or 3.45,you'll have fun for sure,but if you drive aggressive,you'll more than likely be hard on drivetrain parts. lol...
If your 100% sure you'll want to go F/I, especially a manual car,In my opinion,save up some $$$ for a beefed up drivetrain,depends on where you are, if can be a long walk home if something breaks.

[hammdo]

Since you are an M6, the 3.91s will be ok (I have an A6 and switched back from 3.91s to 3.45s)
I have a TruTrac as I road course — helical gearing works best for that
I had an VVT SS1 NA cam and it still worked fine with the blower — you should be ok
Ported heads will help it breath, adding power and lowering boost —thus a pulley upgrade makes sense

My build threads shows what I did to my L99 — on E and ported blower/pulley update made 681/631 RWHP — before I went forged.

I agree with beefing up the drive train first though - it’s what I did too... and Toyo R888Rs...

It’s will become a money pit ;o) my build thread is long but, you’ll see what the LSA kit can do...and what can be added over time...

I’ve done just about everything, E85, Meth, cooling, etc...

Oh, the install guide for the LSA kit is on there too...

-Don

[EM1/SS]

I have the 3.91’s on my 11 convertible with an LSA. I have headers but stock cam. When my LSA was installed and dyno tuned, I was told I was just about at the limit of my fuel system. You may was to plan to upgrade to a ZL1 pump and controller. Plus with the cam, you may want to go with a lower size pulley.

[LevonH]

Just curious but why not trade up to a ZL1 convertible and not go through the anguish of all of the upgrades. At the end of the day you may win on both sides???????????????

[Juiced1]

Your cam has a bit to much overlap for a positive displacement blower but it's not the end of the world. You'll be bleeding off some boost for sure. Between that and the ported heads you'll be able to go pretty aggressive with the pulley. We ran a 2.5" on a ported LSA on our shop car with an LS3 and made over 700rwhp. The gearing might be a bit much but it's not like you have to change it with the blower install. You can drive it around a big and see how it does. If you put a good tire on it you'll need to upgrade the entire rear if you track the car.

[LaN-]

Originally Posted by LevonH

Just curious but why not trade up to a ZL1 convertible and not go through the anguish of all of the upgrades. At the end of the day you may win on both sides???????????????

I've got far to much time, money and pride into this car. IMO I'll end up with a much better car than a stock ZL1 for much cheaper.

[LaN-]

Originally Posted by hammdo

Since you are an M6, the 3.91s will be ok (I have an A6 and switched back from 3.91s to 3.45s)
I have a TruTrac as I road course — helical gearing works best for that
I had an VVT SS1 NA cam and it still worked fine with the blower — you should be ok
Ported heads will help it breath, adding power and lowering boost —thus a pulley upgrade makes sense

My build threads shows what I did to my L99 — on E and ported blower/pulley update made 681/631 RWHP — before I went forged.

I agree with beefing up the drive train first though - it’s what I did too... and Toyo R888Rs...

It’s will become a money pit ;o) my build thread is long but, you’ll see what the LSA kit can do...and what can be added over time...

I’ve done just about everything, E85, Meth, cooling, etc...

Oh, the install guide for the LSA kit is on there too...

-Don

Thank you for the input Don. I've followed your built thread for years now. You're doing a real service to the community.

[LaN-]

Originally Posted by Juiced1

Your cam has a bit to much overlap for a positive displacement blower but it's not the end of the world. You'll be bleeding off some boost for sure. Between that and the ported heads you'll be able to go pretty aggressive with the pulley. We ran a 2.5" on a ported LSA on our shop car with an LS3 and made over 700rwhp. The gearing might be a bit much but it's not like you have to change it with the blower install. You can drive it around a big and see how it does. If you put a good tire on it you'll need to upgrade the entire rear if you track the car.

Thanks for the input. I've decided to just throw the blower on and see how it goes. My goal is only for 550-600 for now.......... Same goes for the rear. If its to much I'll go back to the 3.45.

[LaN-]

Thanks for all the input!

I'm still debating if I should put a LS9 or "sloppy stage 2" cam my buddy keeps telling me about since it will be easy and fairly cheap. However, based on your input I think i'm just going to throw the blower on with the stock pulley, see what it puts down and how it drives.

Also ordered up a set of 305 Nitto 555r's, ZL1 fuel pump with FPCM. Hopefully that will address the traction and fuel concerns.

Finally I put it on the dyno to get a baseline so i have real before and after results.

[LaN-]

[LaN-]

Finally wrapped everything up. Not the same dyno, but she's putting down some solid numbers at 5-6 PSI.

Thanks again for all the help guys!

[LaN-]