Steves post had some great info. Running 13.5 on a very mild 350 is pretty great . I have got to see his car several times at Norwalk just didn't catch him. Matts post of 15.1 with the crower level 3 , big valves, lower compression and a 256 rear is pretty good too. Shows that cam makes the power . you can say it's proven itself.
It's all good Andy. No debate here, just trying to get all the info straitened out and try to clear up the confusion on those numbers. Remember static compression is only one part of the picture. Along with the camshaft's closing point for the intake valve, it determines what's going on inside the engine while it's spinning and moving air around. If the valve closes early enough, it will use more of the static compression to get a higher dynamic compression. Ever seen that buttered toast video? They used a low compression, high mileage junkyard stock engine (untouched, never taken apart), added 6 lbs. of boost and tuned it on a dyno, and came up with 350 hp @4800 RPM and 460 ft. lbs. @3750 RPM at the flywheel.
What's that got to do with anything? Have you ever went to a drag strip on any given weekend you will see a car with an junkyard LS engine high mileage untouched, never taken apart, in it running over 25 PSI turbo boost and making 700 HP to the rear wheels!(not sure what kind of torque they're making?) o No: Kind of makes that sbb 350 junkyard scenario sound lame to comparison and why I would never bring it up. You can put a huge turbo on a GM factory 4 cylinder that only has around 140 N/A HP, run 40 PSI through it and make 1,200 HP! If you try to bump up the boost and get more HP the heads breaks in 4 pieces. We all know that boost will make power, what kind of power can a sbb 350 make without boost should be the real question because not everyone wants to run boost. Plus, the more N/A power an engine can make before boost the more power it will make with boost. This engine is WAY more impressive IMHO; http://www.v8buick.com/showthread.php?200499-the-dyno-numbers-are-in&highlight=1021 Derek
What it has to do with is in reference to what Andy said. Follow along with the bouncing ball, Derek. lol He (among many others here) was having trouble with SAEnet figures vs flywheel figures, thinking they were the same thing. He also said he couldn't see the engine making the power I suggested unless it had boost. I gave a demonstration that this is not the case. I think it's good power out of 40+ year old iron technology on such low boost. Who cares what the new stuff can do? We all already know it's leagues ahead tech wise, so it's no surprise it makes so much more power. ANYthing you can do with a Buick 350 is going to be impressive, considering the lack of aftermarket support it has suffered pretty much its entire life. The point to all this is me trying to clear up some confusion. ...though you do bring up a poignant reminder as to why I consider it rather moot to try and get the Buick 350 to compete with new technology. This is one of the main reasons I like to keep it mostly factory with some tweaking techniques to see what we can get out of one as it came from the factory. To me, that is way more impressive than any sort of aftermarket parts you can throw at it. It's all relative.
I will say that NO-ONE as of yet has done a full tilt correctly done boost setup on a 350 that I've seen anyway except for Finish line and even it had the dual plane and a small blower. If one wanted to realize the full potential of the SBB you need a real Turbo not a Fisher price my first Turbo or turbo's , I'm talking a Pt88,S475,Billet wheel 76, etc and setup with a real honest to goodness hotside and people will start making 800+ without even trying. I've said this many times if you can and I myself have made over 600hp with a 3.8 V6 with their TERRIBLE stock unported heads then there is no reason in the world why a stock 350 can't make the same at the very least with half the boost. I know this a cam help thread but since it's been diverted.... They are very capable as us any engine.. In the right hands
Ah yes, gotcha. In that case I will have to agree with Andy. Of coarse with the '68 to '70 4bbl and "GS" with 10.25:1 advertised compression being the exception to a factory sbb 350 running half way decent performance wise, other than that they were what they were designed for, granny grocery getters. If you're actually working on a factory blueprint engine I would suggest staying away from the "stock" replacement pistons even if your block "needs" to be bored. Find a good set of the '68 to '70 factory 10.25:1 pistons and NOT a "stock" replacement that is "standard" bore size either, if you really want to get close to what you had back in the day. You could save $100 having the block bored as well by just having it honed to the same size and getting the pistons coated to make up for the extra bore size; http://www.line2linecoatings.com/ "Reduce Clearances & Improve Efficiency Thickness 0.0007" - 0.020"+ (18-500+) Build it Tight - Wears in for a long term fit Self-Lubricated Maintains Oil Film Low Friction Scuff Protection Tolerates Foreign Particles Proven in OEM and Race Applications" The last time I checked it cost $240 to coat a set of pistons plus shipping( probably around $40 there and back). Subtract the $100 for honing brings the cost to $180 minus what you buy the used factory pistons for.(bonus if you're starting out with an SP coded engine if I recall correctly to begin with) The coating would be cheating though because it doesn't matter what pistons it is used on the engine will always make more power with that coating than without because of how it keeps the piston more square in the bore and help to seal in compression and more(see above in blue and quotation marks), well worth looking into. With your kind of build you probably would be better of with the older style rods at the power level you'll be at because they are lighter and being a factory blueprint build you would probably never spin it passed 6,000 RPM, if you do then you should of decided to build it better from the get go anyway. Mart runs the older style rods up to 6,200 IIRC and hasn't broke one yet, so.......? Wanted to throw this out there before you have your block bored, if you're even working on something so you don't have to deal with the crappy Federal Mogul "stock" replacement pistons and so you can stick with an actual Buick factory piston. Will probably save you the extra $50 for deck milling if you start out with an earlier block that is only .030" taller than the Buick blueprint dimension of 10.188" combined with a factory piston as well vs. using the crappy "stock" replacement pistons and having to remove an extra .020" to get where it is suppose to be. It should end up around .020" in the hole and with a .020" steel shim type OEM head gasket should be a .040" quench ring, not that it matters that much. Steve mentioned that he measured and mathed out an SP engine and said that with the pistons at zero deck would be 10.25:1, can't remember what head gaskets that was with though. You want at least .040" incase of rod stretch anyway so the piston doesn't smack the head, zero deck and a .020" head gasket should never be used together anyway. Zero deck with the .040" thick Fel-Pro blue head gaskets would work great though. Derek
I'll have to agree with you here. Even though Sean has tried to pump up the boost, he keeps blowing head gaskets through the number 3 cylinder. 2 different engines with the same problem with the common denominator being the Burton Machine S/P intake. Not saying its the intake's fault, but worth looking into? Yeah threads seem to get side tracked because not enough threads to discuss ideas I guess? o No: Derek
And I don't mean to purposely pick on any of the guys using what's available rite now, but there are much better options out there in terms of parts selection like the Carb hats, a bean can with to pipes welded to it is NOT what you want to get boost into the carb, Carb hat entry positions play a HUGE role in distribution and of course this is a direct factor in head gasket failure, burnt pistons,plugs etc.
Tell me more about this 3.8 v6..... Was it a turbo v6 block or not? This 3.8 v6 turbo of yours needs to be a thread with a lot more details.... If it was a buick turbo v6, 600hp is not a big deal.....
Of course it was Turbo and a 3.8 with a stock long block stock cam, stock timing chain, stock untouched heads and intake running 122mph on 93 octane in a full weight 3700lb GN wasn't that common in 2006. Ran 11.0s leaving at 5 to8lbs 7.0's at 98mph. 28lbs with up to 26degrees in 1st an 2nd gear
Check out hairy canary. It a gasser style 67 skylark 350 with fender exit headers and a weiand blower and a predictor carb not top. With 4 speed . Ran 12s and he was having shifting problems. It's easily mid 11s as it was. And I think he can turn up boost still.
You make a good point, once the right person puts all the right parts and pieces together the magic will really show.... Our little toy turbos still did exactly what we were designed to do and that was to make great low and mid range power not just high RPM peak HP... No turbo lag with the small twin setup, it is a very good combo for a street strip car. We even tried a good carb hat on the engine and still had number 3 cylinder head gasket blow so next up is swapping out the custom intake for a TA SP-3 intake and try again.
Did you try an EV "no divider" or pro series Procharger hat? At different clockings? They are the only two that Steve Morris has had any luck with, the rest have issues, properly built carbs are another area guys with Blowthrus get in trouble, home conversion kits usually never work rite, not saying yours are anyone elses is but everyone else ou there in radio land. It's not unusual to have to stagger jet Blowthrus. You also need plenum volume and lots of it , the Xfactor intake is lacking big-time in that department and the SP3 isnt too great either so try a hat and open carb Spacer the air HAS to have a Chance to Straighten b4 hitting the intake floor
And Sean I promise you a Billet wheel S475 or one of the new Gen Turbonetics , Garrets etc would be at full boost on a 350hp SBB faster than you could control it. The new Turbos are leaps and bounds better than 10yrs ago. We have stock little 302's spinning s475borgs to full boost by 3500
All I'm saying is a twin turbo 350cid engine should be in the 6's like falling off a log. I'm not trying to beat nobody up or their setup just help make it faster
I don't want to sidetrack this thread so maybe we should post on my thread here: http://www.v8buick.com/showthread.php?255611-Twin-Turbo-Skylark-350-Progress/page21 It was an EV hat with no divider used at the 6 a clock position, I used a CSU carb custom spec for my combo and the other guy was using another quality blowthrough carb. Both engines had X factor intakes and both killed the head gaskets over and over but ONLY on the number 3 hole. I know you are only trying to help, I have no issue with working together to try to sort out the combos it is just that there are a lot of people who just want to hate and have no interest in helping.
I appreciate your advice and your willingness to help. You've got some good info and you do your homework. :TU: I like the idea of piston coatings. I can always count on you to come up with some interesting ideas on how to improve things. I'm not sure what you and Andy are disagreeing with though, so maybe I'm confused? If it's thinking SAE and brake ratings are the same, then there's really no debate at all, because they were different. The only reason anyone would disagree would be simply either 1) confusion, or 2) simply wanted to be contrary despite the truth--I like to give the benefit of the doubt, so I figured reason behind door number 1 was the logical and sensible choice. You like math too. You tell me what 195 SAEnet hp and 290 SAEnet ft. lbs. equates to flywheel wise. If all you considered was the transmission (no less than 36 hp) and not the AC, taxing alternator, power steering pump, and water pump with a huge clutch fan engaged, it would still be a chunk removed. Even the earlier brake power ratings showed a 'taxable power' figure of 56 (going off memory here) to be calculated in figuring the 'net' power ratings before SAE was used as a standardized rating. This was from my 1968 Buick manual when the only transmission used for 350's was the ST300 2 speed transmission, which only used 18 hp (instead of 36 for the TH350). So if we used this, taking 18 from 56 is 38, so maybe they figured this was the power removed by the accessories (sans transmission), which could indicate 38+36 for the TH350 = 74 taxable used on the SAEnet figures? If this is the case, then we'd see 269 hp and 364 ft. lbs. which is pretty close to what they rated the low comp engines at in 1971, prior to the SAEnet standardization. Or perhaps it's subjective? You consider anything less than 300-350 hp a granny car with no street performance merit? Help me to understand the logic here. While we're on the subject of math, you can also help me to understand where a couple of you guys get 9:1 static from a 10.25:1 factory rating. According to my math, you do not have to zero the deck to get the 'advertised' static compression ratio rating (even with the aftermarket 'crappy' pistons). Maybe on the later models with extra deck, but certainly not the earlier models with higher factory CH pistons. If you were to zero the deck using a set of 10 cc dish '10:1' pistons, untouched 58cc heads and using a .045 composite gasket, you end up with 10.46:1 static compression. Perhaps information from one engine was assumed to be for all 350's and was carried over to another build? Maybe we can iron this confusion out once and for all so it's not parroted over and over elsewhere on other threads as factual information. Thanks in advance!
If your wondering where the 9.2 compression rating comes from . Most 70-75 engines I have measured (hi or low compression) the piston depth is between .058-.060. And as far as that 77 engines at .090 depth adds up as the 68-75 pistons(low or hi comp) are rated at 1.835 compression and 76-80 Pistons are rated at 1.805 compression . .030 difference in Pistons and depth. In summit racings compression calculator. With the specs 3.8 bore,3.85 stroke,58cc head,.045 gasket,.060 below deck. Comes up to 9.18 compression. Now Derek has measured a 350 engine and mentioned about .028 difference in actual block deck compared to blueprint. Round that to .030 off deck. So say .030 below deck and a .020 gasket(factory for 70) and you get actual 10.26 compression. Then as far as how I compare the your rated 280hp 370 lbs 68-71 350 ,drive a 76-80 anemic 140-155 hp 280lbs 350. they would not rated them that low if the numbers are not true. At .090 down hole(76-80 blue engine) with the .045 gaskets calculations of compression is 7.7 . As compared to a 280 hp,370 lbs(70 315/410) 68-70 hi compression engines that have over 1.5 more compression points . That's quite a bit of offset . those 68-71 cars where abundant when you drove them and in 86 - up when I started driving the 76-80 cars where abundant when I drove. Now put the crappy factory catalytic convertor of those cars along with 10 years of wear. The poor flowing convertor choked the hp of the cars I drove and even after getting a 73-74 dual crossmember from junkyard and 2 in duals you ain't getting nowhere near the hp of the early engines.
The various changes to how the numbers were derived and corrected for make comparisons nearly pointless. I think people are trying to point that out and attempt to make a comparison between a useless number and what you would feel on the road... Maybe I'm missing something here? Eliminating a poor flowing Cat. along with restoring a proper advance curve and lightening up the carb's flapper with richer tipped rods was easy pickin's to look like a hero back when these were still being driven daily. I always had a much easier time maxing out the tune on an 8 to 9:1 thingy than a higher one because of the fuel available. If the cam specs aren't THAT much shorter...the power and torque curve doesn't drop too much from a little bit of compression loss. The power potential is still largely determined by the heads, with airspeed through the port (and the related restrictions) determining the peaks, etc.
