boosting ls/vtec

[YOUNGSTER]

ok im getting an ls vtec in a rex it will be done within two weeks. im going with a t23/t4 turbo most likly when he does the ls vtec hes gonna but a low compression head gasket it think it lowers the compression to like 9:0:1 how much boost do you guys think the block can handle and the pistons and rods. thx for any help you guys can give me ive been hearing 12 at the least but i dont know i want to get some other opinions

[eckoman_pdx]

Well, I know the LS can handle up to 12psi on stock internals when tuned properly. I am assuming that since most of the internals are the same and the block is an LS (just the VTEC head), that 12psi would also hold true, do to a very stock like low comperssion of 9.0:1 (thats good, low is good). Don't qoute me on that though, that the same will hold true for an LS/Vtec on stock internals. But since the block is the same, the internals mostly the same and it will have a low c/r, I am assuming that the same holds true...up to 12psi on stock internals when tuned right. While he's got it open and is working on it, I'd have the deck closed. Closeing the deck is one of the steps (besides replacing the internals with stronger parts) required when throwing more boost than the "safe on stock internals" amount at a motor. It will help keep the block from cracking by eliminating the open deck design and instead "closing the deck." Thats just what I would be if I already had the enigne being built and worked on. But still, it's an LS block and internals with a B16A or GSR head (and a low 9.0:1 c/r), correct? Up to 12psi should be fine when tuned right.

[YOUNGSTER]

what do you think would be the max boost when you say closed you mean like a block guard?

[eckoman_pdx]

Originally Posted by YOUNGSTER

what do you think would be the max boost when you say closed you mean like a block guard?

Then Max boost for the LS is 12psi if it's tuned properly, more than any other honda motor. The same should hold true for LS/Vtec you discribed, so I would say 12psi if it's tuned properly. The block and internals are the same, so that shouldn't be a problem. A block guard is the same permise as "closing the deck." That is basically what it does. That will help a lot. It provides a closed area in the deck, preventing the cylinder walls from moving and cracking under high boost. Still, I always perfered closed withdeck with something that goes from the top to the bottem, closing the entire deck area, vs a block gaurd that doesn't go all the way up and down. Still, a block gaurd is the same idea, it will help, and it is definatly better than nothing at all.

[projectsilvia97]

how much would "closing the deck" cost? and when people say built bottom end, what do they mean? thanks

[eckoman_pdx]

Originally Posted by projectsilvia97

how much would "closing the deck" cost? and when people say built bottom end, what do they mean? thanks

Exactly how much "closing the deck" costs I can not say. I know that to have the "bottom end" built, I have seen prices range from $2000-3500 depending on what is done and what brands are used, etc. However, when people say a build bottom end, typically it refers to re-sleeving/closing the deck (re-sleeving w/ closed deck ductile iron sleeves), new stronger pistons (w/ pins and rings) and rods. Also, micro-polishing the crank, a deck, bore & hone, new rod bearings and main bearings, as well as thrust washers can be part of a "built bottom end" or short block. Also, Balancing and Blueprinting can also performed.

Some companies that make Closed Deck Sleeves for resleeving and closing the deck are AEBS and Darton Sleeves.

Darton Sleeves
800-713-2786
760-603-9895
www.Dartonsleeves.com
www.Raceng.com

AEBS (Acvanced Engine Breathing Systems)
858-693-3200
858-693-3449 (Fax)
www.aebsracing.com

[integra818]

Is it really safe to have a boosted LS shortblock go to 8K RPM??? If I were building an LS/VTEC for turbo and I had plans on opening the engine, I'd just start with a B18C1, lower the compression with forged pistons, LS crank (if they fit with the bearings), rod bolts and close the deck.

[eckoman_pdx]

Originally Posted by integra818

Is it really safe to have a boosted LS shortblock go to 8K RPM??? If I were building an LS/VTEC for turbo and I had plans on opening the engine, I'd just start with a B18C1, lower the compression with forged pistons, LS crank (if they fit with the bearings), rod bolts and close the deck.

I have heard mixed things, honestly, about how high to rev an LS/Vtec. some say 7K is it, others say 8K will be fine.

As for why an LS/VTec...simple....it will possess greater displacement than a GSR. A GSR =1797.36cc, an LS/Vtec with a b16A head, will have 1832.17cc (plus the B16A head flows 5.24% better than a GSR). An LS/Vtec with a GSR head is 1831.01cc. Either way, you get the strength and greater displacement of the LS block, plus the Vtec of the other b-series. The greater displacement + vtec gives you more power than a regular GSR, plus the LS blocks strength.

Now, that being said, if you close the deck and through in the forged pistons and rods from you GSR build listed above, you get all the benifits of the LS/Vtec (greater displacement and HP, etc), plus you can now definately go to 8K fine. And with the FI, you will benifit from the extra power from the dispalcement.

[integra818]

Originally Posted by eckoman_pdx

I have heard mixed things, honestly, about how high to rev an LS/Vtec. some say 7K is it, others say 8K will be fine.

As for why an LS/VTec...simple....it will possess greater displacement than a GSR. A GSR =1797.36cc, an LS/Vtec with a b16A head, will have 1832.17cc (plus the B16A head flows 5.24% better than a GSR). An LS/Vtec with a GSR head is 1831.01cc. Either way, you get the strength and greater displacement of the LS block, plus the Vtec of the other b-series. The greater displacement + vtec gives you more power than a regular GSR, plus the LS blocks strength.

Now, that being said, if you close the deck and through in the forged pistons and rods from you GSR build listed above, you get all the benifits of the LS/Vtec (greater displacement and HP, etc), plus you can now definately go to 8K fine. And with the FI, you will benifit from the extra power from the dispalcement.

Who says the LS block is stronger??? I think a GSr or Si block is safer at 8K than an LS block.

One thing that some people fail to realise is that the combination, altough making good power...is NOT an ideal engine. With a head thats meant for an engine to have more RPM and less torque, and a bottom end that's designed for torque but lower RPM...you don't really get a balanced engine.

Besised that, I don't think the bearings in an LS engine will survive while bieng taken up to 8K on a regular basis...esspecially if it's boosted.A better idea is to bore a B18c1 or a B16a2...instead of adding a bigger stroke to it by slappin on an LS shortblock.

The person that figured out how to make the LS/VTEC did'nt reinvent the wheel, I'm sure this has crossed Honda's mind before they made either engine. Altough I do give credit to the guy/gal for bieng bright and figuring it out.

If you're looking to get a high Hp engine for not alot of money, get a chevy big block.

[eckoman_pdx]

Originally Posted by integra818

Who says the LS block is stronger??? I think a GSr or Si block is safer at 8K than an LS block.

One thing that some people fail to realise is that the combination, altough making good power...is NOT an ideal engine. With a head thats meant for an engine to have more RPM and less torque, and a bottom end that's designed for torque but lower RPM...you don't really get a balanced engine.

Besised that, I don't think the bearings in an LS engine will survive while bieng taken up to 8K on a regular basis...esspecially if it's boosted.A better idea is to bore a B18c1 or a B16a2...instead of adding a bigger stroke to it by slappin on an LS shortblock.

The person that figured out how to make the LS/VTEC did'nt reinvent the wheel, I'm sure this has crossed Honda's mind before they made either engine. Altough I do give credit to the guy/gal for bieng bright and figuring it out.

If you're looking to get a high Hp engine for not alot of money, get a chevy big block.

Stronger refers to the Short Block itself. It is a well know fact, an LS can handle upwords of 12PSI ON STOCK INTENRALS when tuned properly. That is a well know fact. You'll blow the b16 or GSR to shit stock at that psi. That means, point blank, the LS block is stronger. So what if a GSR can handle 8k. It's still not smart to redline it to 8K all them time. I'll take the LS block, it can handle 4 more psi of boost on stock internals. Plus, the LS/Vtec has a bigger Displacmant Than a GSR, 1832.17cc to 1797.36cc. That makes a diff. Also, the LS will hit its peak torque A FULL 1000 RPM LOWER THAN A GSR. 127 ft-lbs at 5200rpm. The GSR is 128 ft-lbs @ 6200. The GSR hits peak HP about 1000 RPM later than an LS. And reving ANY MOTOR TO AN 8K REDLINE OFTEN IS NOT GOOD...PERIOD. That increase in displacement size of the LS/Vtec, the ablitiy of the block to handle more boost, 12psi to 8psi, and the fact peak HP and torque are hit a full 1000rpm lower (more useful for the street) is more than enough to make an LS/Vtec potent combo, and better than a GSR performance wise in some peoples opinion. Also, if you have ever seen an LS/Vtec dyno sheet, they make more power than a GSR.....again....It's the Displacement. Now, take that added displacement, and the block that can handle 4 more psi, 12psi vs 8psi. Boost it.....That's one hell of a street motor there. Ask anyone who know's Honda's, these are numbers are well know facts. Besides, Dyno's don't lie.