Is LS/VTEC Bad?

[purpl3ran93r]

OK, So me and my friend where riding is my car talking about his EG coupe, and I said an LS/VTEC setup would be bad unless you built the bottom end, and then we had a friendly argument about it. So am what I saying true, or am I missinformed?

I'm basically said
- Bad to rev past 6500 on stock internals.
- Bad Rod to Stroke ratio
- Bad R/S is bad for High RPMs
- Just get some Cams
- Bad Engine Geometry

Now I'm not saying the LS/VTEC is a horrible engine, I'm just saying
the hassle of building a decent one is not worth it

I got my Info from HERE

 

[Tam4511]

ehhh, technically yes, but you can get away with it sometimes if you do it right
my friend has a b20vtec, his motor is completely stock, and he even ran it untuned for 2 years (its tuned now) and has never had a problem with it

but yes if i were doing it id get forged pistons, rods, arp headstuds, arp rod bolts, GE or cometic HG.

 

[Stopsign32v]

I've often wondered this exact thing. My question is I plan to turbo the car, once I build the motor with forged rods, forged pistons, and rod bolts will I be able to put a Vtec head on and rev it high? (up to 8,500rpms?)

 

[Cripton805]

If you build it yourself and u know how its treated , then it could be a good setup. Too many backyard junkies, just slapping a head on it and calling it a day. Not necessarilly depending on use. The main thing i would say are the slight mods the had and block needs to work properly with vtec. Prepping

 

[Cripton805]

I've often wondered this exact thing. My question is I plan to turbo the car, once I build the motor with forged rods, forged pistons, and rod bolts will I be able to put a Vtec head on and rev it high? (up to 8,500rpms?)

Yeah. I thought n/a

It's hard to trust one already. Just boost an LS. It will cost less and if the engine blows, then it wont hurt the pockets lol

 

[Stopsign32v]

It's hard to trust one already. Just boost an LS. It will cost less and if the engine blows, then it wont hurt the pockets lol

Only reason I want to go Vtec is because when I build the motor I want around 500+whp and I know Vtec heads are better along with better cams (such as the GSR cams are a good choice for boost I've read).

 

[mirrorimg]

There is nothing wrong with an LS/VTEC or B20 VTEC.

The stock LS has a 6700 redline, IIRC. You shouldnt go past that or else you risk rod bolt stretch and spinning a bearing. You will also not see as much power because of the increased compression that the VTEC motor has. It would be nicer if you put some GSR or ITR pistons on the LS rods.

The true LS/VTEC setup includes a VTEC head, a B18C1 block with LS crank and rods with upgraded rod bolts, and GSR or ITR pistons.

- Bad to rev past 6500 on stock internals.
- Bad Rod to Stroke ratio
- Bad R/S is bad for High RPMs
- Just get some Cams
- Bad Engine Geometry

-IIRC the LS can get up to 6700.
-The rod ratio and stroke makes more torque, simple as that.
-The Rod bolts are the weak link in the bottom end, not the stroke and rod ratio
-Just getting cams ($300) wont do it, the LS has a very poor flowing head, and the stock springs cant stand up to the abuse. You will need to upgrade them also (another $300)
-Bad engine geometry? What? The bottom end on an LS is not as good as the GSR or ITR because it does not have oil squirters and the crank is not balanced, and he rod bolts are smaller. The Head on the LS flows poorly and has a less stout design holding the rockers in place. Pairing the two together is (with a little extra work) the best of both worlds.

 

[Stopsign32v]

The bottom end on an LS is not as good as the GSR or ITR because it does not have oil squirters and the crank is not balanced, and he rod bolts are smaller. The Head on the LS flows poorly and has a less stout design holding the rockers in place. Pairing the two together is (with a little extra work) the best of both worlds.

Does this really make that big of a deal?

 

[DC2LSR]

my set up is b18b1 block b17 head...
i have brand new ls crank with ls rods and itr pistons...
like mirrormg said...
i also heard the ls crank is really good an torquey...
i kno plenty ppl with ls/v thats do the same set up n/a an boost that run very hard...
i think its not a bad set-up...

 

[Cripton805]

Only reason I want to go Vtec is because when I build the motor I want around 500+whp and I know Vtec heads are better along with better cams (such as the GSR cams are a good choice for boost I've read).

I thought you wanted street. 500hp on a street Teg won't be very comfy at all

 

[Stopsign32v]

I thought you wanted street. 500hp on a street Teg won't be very comfy at all

Why wont it?

 

[Alan]

With that much Horsepower, you're gonna have some turbo lag, wheelspin, go through lots of fuel, have excessive blowby from high boost levels.

Even a stock block K20, which is a better engine all-together will make around 520 at the wheels at 20PSI on E85.

A friend and shop owner has this exact car making that horsepower, and doesn't drive it many days, if any. It's a strip and super nice, super warm day car. He has 4th gear wheelspin issues under 60 degrees...and that's with a big turbo.

 

[Stopsign32v]

With that much Horsepower, you're gonna have some turbo lag, wheelspin, go through lots of fuel, have excessive blowby from high boost levels.

Even a stock block K20, which is a better engine all-together will make around 520 at the wheels at 20PSI on E85.

A friend and shop owner has this exact car making that horsepower, and doesn't drive it many days, if any. It's a strip and super nice, super warm day car. He has 4th gear wheelspin issues under 60 degrees...and that's with a big turbo.

Well I've heard a Hy35 turbo (which is what I have) will make around 450whp. I don't plan to push it that high, I plan to spend some money on a nice BB turbo, might look into twin scrolls. Why would it go through lots of fuel? Out of boost it should take not much more than a stock motor right? I'll have to look into the blowby since I haven't researched it much but wouldn't that be taken care of with a good set of rings? Again, I'm not real savvy with blowby.

Sorry but with a well setup build I don't think 500whp would be much worse than a 300whp setup.

 

[rockadilla]

There is nothing wrong with an LS/VTEC or B20 VTEC.

The stock LS has a 6700 redline, IIRC. You shouldnt go past that or else you risk rod bolt stretch and spinning a bearing. You will also not see as much power because of the increased compression that the VTEC motor has. It would be nicer if you put some GSR or ITR pistons on the LS rods.

The true LS/VTEC setup includes a VTEC head, a B18C1 block with LS crank and rods with upgraded rod bolts, and GSR or ITR pistons.



-IIRC the LS can get up to 6700.
-The rod ratio and stroke makes more torque, simple as that.
-The Rod bolts are the weak link in the bottom end, not the stroke and rod ratio
-Just getting cams ($300) wont do it, the LS has a very poor flowing head, and the stock springs cant stand up to the abuse. You will need to upgrade them also (another $300)
-Bad engine geometry? What? The bottom end on an LS is not as good as the GSR or ITR because it does not have oil squirters and the crank is not balanced, and he rod bolts are smaller. The Head on the LS flows poorly and has a less stout design holding the rockers in place. Pairing the two together is (with a little extra work) the best of both worlds.

x2
/thread

i personally dont like the idea of a ls/vtec, but thats just my opinion if u want vtec get an engine, not just the head

 

[rockadilla]

Well I've heard a Hy35 turbo (which is what I have) will make around 450whp. I don't plan to push it that high, I plan to spend some money on a nice BB turbo, might look into twin scrolls. Why would it go through lots of fuel? Out of boost it should take not much more than a stock motor right? I'll have to look into the blowby since I haven't researched it much but wouldn't that be taken care of with a good set of rings? Again, I'm not real savvy with blowby.

Sorry but with a well setup build I don't think 500whp would be much worse than a 300whp setup.

ha! i think it depends on how good of a driver u are, do u really know the exact difference between 300whp and 500whp? not saying that ur wrong, but i think that if i got my car to 300whp from the 120ish it is now that would make a HUGE difference, so going from 300 to 500 should also be HUGE difference. but i could be wrong. just my thoughts.