knievel

iTrader: (11)

please stop posting

OneBadLS

whats your input then . Id love to hear unless you like to just criticize people.

6.0Nova?

I don't know about kinevel, but I'll throw my 2 cents in the ring. It doesn't matter what you're using to get boost, turbo or supercharger, but either way, you'd be better off with lower compression. It's all about cylinder pressure...too much and *** breaks at a fantastic rate.

BTW, where on God's green earth are you getting your Ford info? Or your science? The reason the older aluminum Ford blocks are so much better is that they were cast by Teksid of italy and are much more heavily reinforced than basically any other Mod motor block out there and can stand something like 1500hp, though the newer Ford produced aluminum blocks are pretty beefy in their own right. Cast iron is stronger, as someone already mathematically demonstrated earlier on, and that's why Ford picked an iron block for the 03-04 Cobra Terminator motor; rumor was at the time that they were concerned about the strength of the newer Alum. blocks.

Personally, given the choice between an iron or aluminum LSx block, I'd probably choose iron, unless I had something specific in mind that required light weight. The iron block can take more in every respect, it's not THAT much heavier, and it's much cheaper and easier to find.

blackhawk400

iTrader: (1)

I agree with 6.0nova. the big generation 3 iron blocks (lq4 and lq9) are very good blocks for any build. they weight around 80lbs more than the aluminum gen 3 motors. and theyre very easy to find, and cheap too.
onebadls... i think you should read 'street turbocharging.' its a great book on turbo setups and the math behind them. in regards to your statement, all forced induction whether turbo or supercharged need low compression for better results.
back to the o.p. if your getting the motor out of an ss silverado, i believe its an lq9. personally, if i had the cash, i'd be swapping out my lt1 and dropping in one of those with a stroker assy and a big cam.

OneBadLS

I know that but you can go either way with FI, most people go with a lower compression because its much easier to tune. running a higher compression will result in quicker spool time and more HP but its simply not that safe. thats why most tuners do lower compression.

6.0Nova?

You "can't" run high compression on a turbo motor with any significant amount of boost. Yes, the Paxon-supercharged 1966 Shelby GT350s ran 10:1 with a blower, but those things put out 6psi on a good day, which means the cylinder pressures were pretty sane.

People do NOT run low compression boosted engines because it's easier to tune, they do it because the engine won't survive for very long otherwise, since if you were to run a high boost, high compression motor, the high cylinder pressure would set things to breaking in a hurry.

Wait, maybe my buddy is doing it wrong...I mean, it's only running 75psi of boost on low compression with the little turbo, maybe he should build a high compression motor with the big turbo and set it to 95psi boost?

Seriously, I don't know where people come up with this garbage. You seem to believe your own BS.

OneBadLS

No kidding dude I just said that, its easier to tune and its more reliable, what I am I saying that is so wrong to you people.

I don't get how I am wrong, you basically just repeated what I just said about running higher compression will blow a rod or piston etc. I just said that. Thats what a higher compression would do.

running a lower compression is somewhat restrict for power unless you upgrade the pistons, connecting rods etc.


Ask anyone outside of domestic, more times then not they say their running a lower compression because A. its more reliable and B. More easier to tune.

I don't understand everyone mixing up my words etc.

rao

iTrader: (18)

Is this thread somehow about an engine swap?

blackhawk400

iTrader: (1)

like i said, onebadls, you should really read up on turbo systems. whoever you learned about forced induction from obviously didnt teach you the right stuff.
there is no going either way with fi. the lower the cr, the higher the possibility for boost. tuning isn't easier either way, actually it has nothing to do with the motor itself.
also, running higher compression doesnt result in faster spool time. spool time has to do with the size of the turbo and exhaust pressure and quantity from the motor.
it might do you some good to read some of the threads under the fi section as well. no offense, but you seem to have boost theory a little confused.
a solid built 11:1 compression motor might be able to handle 8psi.
the same solid built motor with lower compression pistons and higher cc heads running at 8.5:1 compression could maybe handle 30psi.

/hijack

ps, lets stop arguing about compression ratio and help out the o.p.

6.0Nova?

Because you can't "TUNE" a high compression, high boost motor to help it survive. Utterly false. I am NOT repeating what you said; you never said half that stuff. You said that such an engine would be "harder to tune". How in the green blazes that equates to "will blow a rod" I do not know. Granted, you'd have been correct if you'd said "will blow a rod" or something equivalent, but you didn't, and that's where you fall into the wrong.

How is my buddy making well over 700hp and 1500tq on 75psi boost if running low compression is such a restriction when it comes to making power?

And, does "ask anyone outside of domestic" mean ask ricers about how to build a boost motor? Half of those guys are more interested in their PS3s and their body kits than making HP and some of them that do have a clue about cars aren't too good with turbos and such, plus it's a bit of a different world over there; their electronics can do strange things, not to mention that your garden variety Honduh block can't hold a lot of boost...

I do apologise for the hijack...can we get back to talking about this fella's LQ9 swap?

OneBadLS

I will quote my self, I already said its easier to tune a lower compression engine then it is for a higher compression engine. I put it in Bold words If you couldn't read it.

Once again read my above post, I said nothing about tuning a high compression engine.

OP.
On a side note, Yes the LQ9 Is basically the same as an LS3, much better platform and most things are transferable to the LQ9 from the LS3.


On a side note I would definitely contact one of the vendors on here, Most guys would go with Trick Flows Heads. If I am not mistaken they're may be some people running LS7 heads.

FeloniousMelon

if youv got money and dont want anything over 500hp'ish go with an aluminum.
but if youve got a tight budget or want to go crazy horse power pick up an iron.


and to "onebadls"... it doesnt just have **** on there... its actually got some useful info

frojoe

iTrader: (10)

And he isn't saying your wrong because that is your soul justification. It's just simply that lower compression imparts less stress on the engine initially, and thus easier to add more boost into without having to build/beef the whole assembly.

You are right that it's easier to tune a lower-compression engine I guess, because you won't as quickly arrive at that fine "tuning" line with the cylinder head pressures and timing retardation, but really for either application, tuning a boosted engine is tricky, too many variables to make it a cookie-cutter application.

Also, it comes down to heating. The more you compress air, the hotter it gets. Turbo/Super chargers get away with this with intercoolers. The only "intercooling" the cylinders have is the coolant. So naturally, for a cylinder full of already-boosted cold, dense air, the less you compress it, the less it'll heat. But then that gets tricky because cold/dense air is desired for fitting more air INTO the cylinder, not necessarily too important how warm it gets AFTER as much air as possible is in there. But then the hotter the air/burn gets, you have to worry about melting pistons, rings, valves, plugs, etc.

Point is... tuning should NOT be the #1 reason for compression selection in a boosted application, for anyone, no matter what the budget. Engine life is the main factor. And if someone wants to justify a costly engine rebuild with high compression+medium boost, they got their head on wrong, it should be justified with lower compression and HIGH boost!!!

Holy crap, SORRY TO THE ORIGINAL POSTER... I got carried away

Did you mean LS2 perhaps? You have to worry about the relucter wheel, and crank/cam sensor location, those might mean you'll have to modify the harness, but I'm not sure. This is not a warning that they're different, just that you should check into those.

Everything else externally will fit, such as intake/accessory drive/oilpan/trans/heads. Except the LS7 I think, I heard that LS7 heads need their own different intake???

UnZFeat'd

iTrader: (1)

hah... i guess!

Anyway, im pretty sure that the motor is an LQ9. Ive been reading up a lot on them and it seems like a good idea to swap it in. I have a wet nitrous kit setup on my car right now with 75 shot jets and jets for 100, and 150. I know the LQ9 would be good with turbo/supercharging, but what about when it comes to spray? How much bigger can i go as far as cam size and I want to try to get a set of L92 heads if i can find them cheap enough. Could i go with a bigger shot safely? Fueling aside.

BillyBob750

This thread is FULL of WIN!

juiced_z28

iTrader: (12)

OneBadLS, you better have a hot mom to show us some nude pictures of or like material of hot girlfriends. Because otherwise you are absolutely 100% worthless to the car community at this point. I can't believe people are arguing with you, please contribute something worthwhile or delete your account.

claytonisbob

iTrader: (1)

LS7 heads on an LQ4/LQ9 are a no go due to cylinder diameter.

OneBadLS, no matter how strong you build an engine... High boost w/ high compression is just not going to work on a gasoline engine. I believe you'd start running into major detonation issues if you do. Show me an example of a high compression (10.5:1+), high boost (15psi+) engine that runs well, import or domestic, iron or aluminum. Going with lower compression facilitates higher boost and more power. It really doesn't have anything to do with tuning. A good tune is a good tune, most of the guys that would go out of their way to FI an engine are probably going to spend some time an money tuning it. This is not about what is reliable, its about what works or not. In this context, those are different things.

Look man no offense, but if this many people are disagreeing with you and nobody is backing you up... it may be time to go read some more.

Just realized this thread had nothing to do with FI... interesting. That being said if you are going FI and are keeping the bottom end the way it is for a mild setup, a later LQ4 would be the way to go. If not the LQ9 is a nice higher compression version. If your going to build the bottom end, either will do (with the LQ4 being more affordable and easier to find)... but that probably goes without saying to the OP.

6L.IROC-Z

iTrader: (6)

Thanks for the lol I needed it. I really wish I would have read this thread before I swapped in my power robbing iron block .

OneBadLS

Ha ha... your funny did your mom give you that joke?

On a side note, I never once said anything about tuning a higher compression motor, I simply said it is easier to tune a lower compression motor then it is a higher compression motor.

I am not worthless to the car community, I am more or less into imports but like most cars in general. Also don't tell me to delete my account. I have my opinion and so does everyone else.

If you like to criticize people you much better off not posting at all. Like the old saying goes "You don't have nothin nice to say don't say it at all".

I have nothing against anyone here. And I am willing to learn, sometimes you gotta make mistakes in order to learn. Obviously I learned something new no need to bash over it. After all it just shows your an e-thug.

406 Q-ship

iTrader: (1)

Another internet "expert"