Engine build up for a turbo
07-16-2003, 03:05 PM
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Engine build up for a turbo
I just dropped a B18B in my CRX and added a couple bolt-ons (intake, 3" cat and catback-exhaust) I am planning on getting a turbocharger in a couple months. Right now I'm looking at a couple different kits and trying to sort out what I can accomplish long term. I want to complement the turbo with some engine work that will help make the most of it. My question is what kind of engine work will help me take advantage of the turbo. The engine is middle aged ('95, 80k) and i am looking to balance reliability, performance, and drivability. I intend to keep this car as my daily driver and perhaps use it on the track every once in awhile (more auto-x than drag)
HP goal is abour 250whp and I want to keep the torque as much as possible (i.e. not overly peaky HP curve). Oh yeah I plan on spending about 10k on the engine over the next year or two so price cant be too much as the turbo setup will probably take about half that.
Here are some considerations:
1) Forged rods, pistons, crankshaft, sleeves
Seems like a no brainer. Stronger bottom end will allow for more boost and better reliability. Can I safely raise the redline with these mods? The b18b has a low redline and a big turbo might need more revving.
2) Bigger bore
No replacement for displacement? What exactly is the downside (aside from cost)
3) Higher/Lower compression
A lower compression ration is supposed to be better for boost right (less chance of detonation?). However a higher compression engine can make more horsepower with less boost which allows for a smaller faster spooling turbo (like the greddy maybe?) The stock CR for the B18B1 is 9.2:1 so should i be heading up or down from here?
4) Random other block stuff
Block gaurd or a girdle? Needed to prevent major engine failure? Do I have to worry about this kinda stuff at 250hp??
5) Port&Polish
Another no brainer? Worth the cost? Neccesary?
6) Camshaft
I assume that turbo cams will help me keep my boost in (less overlap between intake and exhast). Do I need this if I stay to a lower boost level or will it help regardless?
??Any suggestions??
HP goal is abour 250whp and I want to keep the torque as much as possible (i.e. not overly peaky HP curve). Oh yeah I plan on spending about 10k on the engine over the next year or two so price cant be too much as the turbo setup will probably take about half that.
Here are some considerations:
1) Forged rods, pistons, crankshaft, sleeves
Seems like a no brainer. Stronger bottom end will allow for more boost and better reliability. Can I safely raise the redline with these mods? The b18b has a low redline and a big turbo might need more revving.
2) Bigger bore
No replacement for displacement? What exactly is the downside (aside from cost)
3) Higher/Lower compression
A lower compression ration is supposed to be better for boost right (less chance of detonation?). However a higher compression engine can make more horsepower with less boost which allows for a smaller faster spooling turbo (like the greddy maybe?) The stock CR for the B18B1 is 9.2:1 so should i be heading up or down from here?
4) Random other block stuff
Block gaurd or a girdle? Needed to prevent major engine failure? Do I have to worry about this kinda stuff at 250hp??
5) Port&Polish
Another no brainer? Worth the cost? Neccesary?
6) Camshaft
I assume that turbo cams will help me keep my boost in (less overlap between intake and exhast). Do I need this if I stay to a lower boost level or will it help regardless?
??Any suggestions??
07-17-2003, 04:16 AM
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Aight i'll give ya some short a dirty answers. I'm on my way to work, but i'll get a bit more detailed after I get to work.
1)LS engines have no aversion to being revved, they just don't make power in stock form. This is mostly due to cam profile, LS cams are only slightly more agressive than DOHC VTEC low cams. If you've noticed above about 6~6.5K you LS falling on it's face, that the cam profile mostly. Another thing to consider is that most naysayer will tell the the LS' rod stroke isn't good for revving. A GS-R's R/S ratio isn't but 1.57 against the LS' 1.54.....And GS-R's rev to 8K alll day long. Forged internals, balancing, and a proper valve train and you can safely twist the LS to 8500, higher if you've got the balls or the ability to makepower that high. I run mine up to 8K.
2)Only down side to bigger bore is that you can't go above 84~84.5mm. Some will say it reduces your ability to rev, due to the fact that you're adding more rotating mass with the large bore pistons. However I just don't see it on a built engine, that has been balanced and spec'd out right.
3)8.5:1~9:1 compression is the sweet spot for boost and tunability. Higher compression does yeild more more, but also a much smaller tuning window to prevent detonation. I was gonna run 10:1 compression on my engine and make some serious HP numbers of low-moderate amounts of boost. However for a street driven car that presents the problem of keeping the detonation down and various other tuning issues.
4)Honestly you can hit 250whp on a stock LS block and about 10~12psi of boost on a decent t3/t4. Many people have run 10~12psi on stock block LS's for a very long amount of time. If you keep the LS tuned right it'll run almost indefinately at that level of boost. For some reason LS's take very well to boost. I know a very respecable tuner that has/does run 20psi through a stock block LS for a good while now.....
Also I do run a girdle on my 2.0L LS
5)LS haeds have got be the absoulte worst flowing of the b-series. A very minimal gasket match port job on the intake and exhaust makes a very big difference. A full head work-over would make an even bigger difference. P&P helps out a lot on the LS heads, 'nuff said.
6)Turbo cams are a sketchy thing, there aren't really any out there that have been dyno proven with results. I run a custom set of high lift/low duration cams, but thats just my choice. Any mild to moderate N/A cam will make more power than the stock LS cams......that suck ass
Fire off any more questions. I've been here for a long time, I just dont post much any more, but I lurk around.
1)LS engines have no aversion to being revved, they just don't make power in stock form. This is mostly due to cam profile, LS cams are only slightly more agressive than DOHC VTEC low cams. If you've noticed above about 6~6.5K you LS falling on it's face, that the cam profile mostly. Another thing to consider is that most naysayer will tell the the LS' rod stroke isn't good for revving. A GS-R's R/S ratio isn't but 1.57 against the LS' 1.54.....And GS-R's rev to 8K alll day long. Forged internals, balancing, and a proper valve train and you can safely twist the LS to 8500, higher if you've got the balls or the ability to makepower that high. I run mine up to 8K.
2)Only down side to bigger bore is that you can't go above 84~84.5mm. Some will say it reduces your ability to rev, due to the fact that you're adding more rotating mass with the large bore pistons. However I just don't see it on a built engine, that has been balanced and spec'd out right.
3)8.5:1~9:1 compression is the sweet spot for boost and tunability. Higher compression does yeild more more, but also a much smaller tuning window to prevent detonation. I was gonna run 10:1 compression on my engine and make some serious HP numbers of low-moderate amounts of boost. However for a street driven car that presents the problem of keeping the detonation down and various other tuning issues.
4)Honestly you can hit 250whp on a stock LS block and about 10~12psi of boost on a decent t3/t4. Many people have run 10~12psi on stock block LS's for a very long amount of time. If you keep the LS tuned right it'll run almost indefinately at that level of boost. For some reason LS's take very well to boost. I know a very respecable tuner that has/does run 20psi through a stock block LS for a good while now.....
Also I do run a girdle on my 2.0L LS
5)LS haeds have got be the absoulte worst flowing of the b-series. A very minimal gasket match port job on the intake and exhaust makes a very big difference. A full head work-over would make an even bigger difference. P&P helps out a lot on the LS heads, 'nuff said.
6)Turbo cams are a sketchy thing, there aren't really any out there that have been dyno proven with results. I run a custom set of high lift/low duration cams, but thats just my choice. Any mild to moderate N/A cam will make more power than the stock LS cams......that suck ass
Fire off any more questions. I've been here for a long time, I just dont post much any more, but I lurk around.
07-22-2003, 06:07 PM
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wouldnt it just be easier to go all motor on this one? im not sure how much HP a b18b makes but im guessin sumwhere around 120-150??
07-22-2003, 06:13 PM
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All motor is probably the best way to go, especially for reliability. The LS motor is a good starting point, especially when B18C1 and B18C5 head components, etc. swap right on.
Good luck.
Good luck.
07-22-2003, 06:33 PM
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Urgh, you people obviously don't know the power of the dark side. $3000 in all-motor work gets you 30~40 horsepower. $3000 worth of forced induction get you 100+hp and gobs of torque.
07-24-2003, 01:35 PM
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If I wanted to go all motor i wouldnt have gone out and bought a B18B. Doesnt make sense does it? I would definatly need a VTEC engine it i wanted to go all-motor. I got the B18B because its cheap and I like turbos.
07-25-2003, 10:36 AM
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Re: Engine build up for a turbo
1) First off, don't replace the crankshaft unless you're chasing record times. It's forged from the factory, and will stand up to tremendous horsepower.
Second, LS engines do not like to rev from the factory for a variety of reasons. I would never rev a Honda past OEM redline with stock valve springs, but beyond that they lack a girdle and don't seem to be balanced as well. Of course, that can all be taken care of when you redo the bottom end.
2) Downside: Thinner water jacket, worse overall cooling. This varies a lot based on manufacturer and sleeve size.
3) 8.5-9.5 is a good ballpark. I'd stick at 9 or 9.5, personally.
4) You don't have to worry about a girdle at 250 HP, but if you're rebuilding the bottom end it's $200 of peace of mind. Plus, you won't have to peel off the oil pan again later. I'd stay away from block guards for cooling reasons.
5) NonVTEC engines just weren't designed or made for performance, and as a result their heads do not flow as well as VTEC heads from the factory. A good port and polish can do a lot, but I'd caution you against going all out on P&P with an LS head... I think you'd get better results with a polished VTEC head, and a good P&P isn't cheap.
6) Help regardless.
Second, LS engines do not like to rev from the factory for a variety of reasons. I would never rev a Honda past OEM redline with stock valve springs, but beyond that they lack a girdle and don't seem to be balanced as well. Of course, that can all be taken care of when you redo the bottom end.
2) Downside: Thinner water jacket, worse overall cooling. This varies a lot based on manufacturer and sleeve size.
3) 8.5-9.5 is a good ballpark. I'd stick at 9 or 9.5, personally.
4) You don't have to worry about a girdle at 250 HP, but if you're rebuilding the bottom end it's $200 of peace of mind. Plus, you won't have to peel off the oil pan again later. I'd stay away from block guards for cooling reasons.
5) NonVTEC engines just weren't designed or made for performance, and as a result their heads do not flow as well as VTEC heads from the factory. A good port and polish can do a lot, but I'd caution you against going all out on P&P with an LS head... I think you'd get better results with a polished VTEC head, and a good P&P isn't cheap.
6) Help regardless.