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| slant rebuild/build up https://slantsix.org/forum/viewtopic.php?t=40325 |
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| Author: | Evilsizer [ Thu May 20, 2010 8:32 pm ] |
| Post subject: | slant rebuild/build up |
trying to figure out what it would take. to achieve a 1hp per cube on a non-bored/stroked 225. what would need to be changed, cam, etc? i figured the intake would need to be changed to say a aussie speed 4bbl. At the least but i could be wrong. does anyone know of any place that has dyno numbers for stock slant 225's. With different carb setups as the only change? thanks for any help! |
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| Author: | Fopar [ Thu May 20, 2010 9:03 pm ] |
| Post subject: | |
Big change if you up the compression ratio & change cam |
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| Author: | SV162 [ Thu May 20, 2010 9:11 pm ] |
| Post subject: | Re: slant rebuild/build up |
Quote: trying to figure out what it would take. to achieve a 1hp per cube on a non-bored/stroked 225. Yep, up the comp and cam change. I'm no expert but to start with I'd say you would need to do a lot of work on the head (bigger valves, port/pollish/shave) intake and exhaust upgrade, I don't think you would need to go 4BBL carb but it wouldn't hurt. I let those that know more than me expand on the above. 
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| Author: | Evilsizer [ Fri May 21, 2010 6:56 am ] |
| Post subject: | |
ok so we raise the compression,9:1 or higher? can that be done by using longer rods? such as the 170ci rods DD puts forth in stroking article. lets say i want peak HP around 4.5k rpm what kind of cam would be able to do that? Would it be better to look for it around 5k instead? would it be easier to go with a turbo instead if going with EFI? |
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| Author: | SV162 [ Fri May 21, 2010 7:14 am ] |
| Post subject: | |
So many questions. Easiest way to make HP is NOS. You're engine may not last too long but it would be fun.  What's your plan for this engine? P.S. I think you mean 198 rods. |
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| Author: | Evilsizer [ Fri May 21, 2010 7:40 am ] |
| Post subject: | |
yea your right for some reason i was thinking it said 170 rods... just street, around town driving and some hi-way 60-70mph. |
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| Author: | Doc [ Fri May 21, 2010 8:59 am ] |
| Post subject: | |
OK... you say "street car" so it is better to talk in terms of torque, instead of HP. Trust me, lots of torque is really what you are looking for, not some arbitrary HP number. (225 HP in this case) Example, it is pretty easy to get 225 HP out of a SL6... spin the engine at 6500 RPM and that HP number comes easy. Getting 225 HP at 2800 RPMs is a different story, that's where lots' of torque comes-in. Anyway, like others said, more compression, careful head work to keep intake volocity in the chosen operation range and the right cam is the foundation to a high torque street engine. See this paper on more torque vs HP discussion and some basic formulas to help calculate the relationship between HP, Torque and RPMs. DD http://www.epi-eng.com/piston_engine_te ... torque.htm |
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| Author: | DusterIdiot [ Fri May 21, 2010 1:17 pm ] |
| Post subject: | Yep... |
Quote: OK... you say "street car" so it is better to talk in terms of torque, instead of HP.
Two rules I've incorporated into my philosophy with regard to street and performance:"I'd rather take 10 more ft/lbs of torque in the lower rpm range than 10 more HP at the top end when dealing with a heavier car"-David Vizard "Notice that if you match the camshaft's torqueband in the useable power range/driving RPM, you also maximize your gas mileage in a street engine"- my machinist... If you up the compression through milling, you might as well overbore so you have a good straight bore to seal to, and use good rings as well...good head work is a must. -d.idiot |
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| Author: | Evilsizer [ Fri May 21, 2010 4:18 pm ] |
| Post subject: | Re: Yep... |
well what if i just say a 25% increase in torque at 1600 rpm over stock. which is 212ft lbs but closer to 225ft lbs would be cool. just assuming worst case and only can get 200ft lbs at 1.6k rpm, what kind of cam to make it as broad as possible with it making max torque (what ever it might be, not sure) around 4-4.5k. Just keep in mind im more computer oriented them i am mechanically inclined. though i am willing to do what work i can my self. not everything sticks with me or makes sense the first time i read threw it. *edit* i recall reading something about someone or company. doing new casting for /6 blocks? would be interested in getting one if they have some kind of ALU-alloy block. |
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| Author: | VG-265 [ Fri May 21, 2010 4:47 pm ] |
| Post subject: | |
Thanks for the EPI link  That website has some fantastic info. |
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