Yunus

Hello Hello,

I have been doing a research regarding my own engine ( yeah I know I know ) ... Well I bought the Z06 as is and I have the built sheet pretty much... All I have regarding the engine is listed below.

Car is built by LMR in Houston and the Engine is built by LME.

I visited both shops to find out the compression ratio of the engine but no luck. They haven't kept the info so they were not sure ( what the heck! its a 20 Grand Engine )

Anyway, the previous owner said that the heads are rebuilt and milled to raise the compression because he was gonna go Nitrous.

The shop I take my cars to , looked at the specs and said we can boost it.
I trust him but people make mistakes and I don't want to be a victim if that's the case. That's why I am trying my best to gather information about my built.

I have a procharger P1SC in hand.

So my question is , looking at the built below , would you think its okay to procharge it ? How safe it would be ?
How many pounds of boost would you do if yes ?

Would you suggest e85 or meth injection to be safer ?

ETC ETC ...

I really appreciate any input!

Thank you

Car made 620hp To the Wheels on DynoJet

Its a 440 stroker Shortblock LS7 ( GM )

Callies Dragon Slayer 4.100` stroke crankshaft w/ls7 post and 58x reluctor

Callies 6.125` H Beam Rods w/ arp 2000 7/16` bolts.

Diamond Custom 4.135` forged Turbo pistons

NRP stainless chrome rings 1.2 1.2 3mm ( for high heat applications)

Clevite ms 2199 H main brgs,

Clavite CB663 H rod brgs

Dura Bond Cam brgs and Arp Studs.

LSX COMP CAM .625 lift 114 LSA

ARP HEAD BOLTS

GM head gaskets

COmp OE lifters
NGK Spark Plugs Iridium Plugs
LS7 Crank bolt
Water pump gasket , oil pump inlet tube , front cover , crankshaft front seal , oil pump inlet tube , O ring

vertC6

First off you need to get a compression tester and find out the compression. Personally I have always preferred higher compression would lower boost because it makes less heat, And remains good drivability.

Second I would definitely go with a flex fuel sensor from D Steck so you can run 93 and E85 because we have stations all over town. However with a blown car you will need to upgrade the fuel system.

Third what are your cam specs? You may need to change the cam to a more blower friendly spec.

Yunus

I got it checked and it said 10.5 but as far as I know they are not perfectly accurate. That makes me think. In order to get the perfect compression , the engine need to be taken apart, correct me if I am wrong.

The car has a lot more to It and I didn't list it but I am aware of the fuel components etc.

e85 is an option for me yes but I don't know how much it would help if my compression is way too high for boost?

I don't want to **** it up and drive my corolla on the weekends

vertC6

10.5 to 1 compression is perfect for boost, you can easily run 10 psi. A Good compression tester is all you need, check multiple cylinders and it will tell you if it's accurate. E85 will allow you to run more timing on boost and make a lot more power while keeping it safe. It runs cleaner and cooler! Your true compression under boost will be around 18:1 so yes E85 will definitely help And I drive my Tundra when my baby is in the shop!

Yunus

Thank for the info.


It seems like you trust the compression tester ?
What in my case doesnt make sense it that the heads milled to raise the compression and it now reads 10.5 ... I just cant trust the tester.

I think I ll do e85 or meth injection for sure tho.

vertC6

The Pistons, you said turbo pistons which means they're low compression, probably a dish and he milled the heads to bring it back up

Yunus

I hear you.
That was my concern, probably part
LME also said it is probably okay to boost.
Well I guess I ll go ahead and do it but I feel like I am taking a slight chance here

Thanks for the help

vertC6

With LME building that motor with those parts you should have very little risk if tuned correctly

Michael_D

An OEM block with OEM cylinder liners, and 4.1" stroke with heavier rods, and you want to boost it too? I would not recommend boosting it.

Unreal

Agreed.

A stroker will have pistons with thinner ring lands too.

Yunus

Even 6lbs boost ??

Unreal

Your money, your car.

I wouldn't put a procharger on anything I own, but that is me.

Yunus

Well thats a strong statement! I never heard anyone disliking procharger to be honest

Unreal

Wow, must not hang out here often, or on YB.

Never had luck with their kits. I know a few people on here have, but my personally experience has been very poor and the ECS/A&A kits are much much better from my experience, and cost less.

vertC6

I can't image anything built from LME couldn't handle 6 psi. When you said "forged turbo pistons" is that a type of piston or one designed for turbos?

I do agree the A&A and ECS are the best, I love the powder black kit that A&A sells with the V3 - Si Vortech. Truly a great kit. The problem with the procharger is more the bracket than the head unit itself. I would sell it and buy the A&A kit if it were me.

Yunus

Well thats the only info about my pistons.
on the sheet, it says exactly like that. Turbo Pistons.
I assume its designed for Turbo applications.
but I assume

Michael_D

It’s not that LME doesn’t build stout engines that can handle a little boost, it’s that they didn’t build this one with boost in mind. Or, maybe they did, but we don’t know that. I suspect not though. The liners are just don’t hold up to power adders all that well. The cast alloy is brittle, so it tends to crack towards the top if you are not careful with spark and fueling. When you add stroke, you raise piston speed, as well as increase the rod angle, which puts more thrust on the liners. Then add rad weight, and thrust is increased further. Now, add some boost, and you’re walking a tight rope. And also, with the longer stroke, you move the wrist pin closer to the top of the piston, so as Unreal mentioned, the ring lands get smaller and the top ring may even be move upward, reducing the amount of material between the compression ring and top of piston. All of these little things start to add up.

Yunus

Michael D , I hear you very well.
Then in this case, if the purpose of the engine was nitrous or meth etc.. why did they use turbo pistons ? That makes me think and move towards procharger since I have it in hand.
I have another assume that the turbo pistons dropped the compression low so they milled the heads to raise it up to match maybe 11.1 or it is maybe lower as my tuner tested at 10.5

just brain storming here

Michael_D

How do you know it's 10.5/1? SCR is a calculation of swept volume, knowing combustion chamber CC, piston relief CC, gasket and piston height. It's not compression.

I don't know what "Turbo Pistons" means. Could be anything, and the designation is irrelevant. Kinda stupid really. A better description would have been.... Forged with 15CC dish, directional....

Meth cools the combustion chamber. It's great for running more cylinder pressure and reducing detonation. Spray is a bitch. I hate it. There is always something going wrong with that crap. But, some guys still want it, so I build them engines to use it. Then they show up with the engine in the back of a pickup an a sad look on their face.....

I have no opinion on the various superchargers. I'm just telling you what I see from your engine description, and what I would do, not do. And I would not boost that engine if the liners are OEM.

Unreal

Even if the piston is correct, and is a good FI piston to support 2000hp, does it matter if the cylinder walls, block, rods, etc aren't up to making the power? Only takes one weak part.

I would not boost a 440+ci stock liner motor without all the details.