Yeah, one way is to drop DCR very low. You really only need to reduce it a little bit though. Other aspects are raising the rpm range before the engine can see load, reducing the sweep rate in gear, managing inlet and coolant temps (worth a few octane #'s), eliminating any incandescence. Machining specs such as quench become vital. Small bore, long stroke engines do much better with lower surface to volume ratios than big bore, short stroke. Throwing more oil at the underside of a piston, wider exhaust seats...both tremendous heat transfer tactics. Even in high octane fueled engines, these methods are still needed. Budget circle track uses this "fancy trickery" the same as every other hard run engine. Apply some towards your max effort street engine. It helps if you are the machinist. An important x-factor that is math-able is mixture motion. Whether you are talking about swirl used below a certain rpm range, tumble higher up, or the ramps required by the direct injected engines needed to atomize fuel better than an injector possibly can...the engine doesn't really care. The most modern head porters have been introducing these methods. Widmer is an interesting historical study, for one. As far as utilizing a trapped compression "formula", major factors to calculating the auto-ignition temperature of the fuel in question is the temp of the engine's surfaces, the inlet air temp, the presence of end gasses. Should be easy to google some formulas there. This is really basic stuff decades old. Guys like Lingenfelter studied emissions and worked with OEM's before utilizing their education on combustion technology towards the caveman-ish hot rod moter. "They've" (including OEM's) have known what they've known for a very long time. Only recent tech additions to this are things like high pressure transducers and the use of computers, etc. To benefit from the unobtainable you really only need to think about things a little bit, then establish a working baseline. Oh yeah, before I forget...heat crossover...blah blah...cold weather...blah blah...
Larry I'm very aware of the new cars,and that they have efi, and there computer tech, and sensors, a long with over price stuff, etc. I just stating newer cars run warmer, for a reason. 195 temp has nothing to do with technology, sensors, and other junk. Both of my buick 350 had 195* thermostat, not 160, 180 or 185. In the end I was just agreeing that engine a to run prime around 195 temp. And I don't drive like miss daisy, I drive my old police vic. Pedal to floor A LOT. I agree with you last on the temp I'm trying to bring mine down on an A/C car in a 84 buick regal with 350 in it. On hot days it creeps to 215 going 70 mph at 3100 rpm and ac running. Josh
Well with all this talk about plugging the cross-over ports in the heads, we pulled the intake off our Buick, and tried to install 3/4" frost plugs. I was able to set them in with my finger down over 3/4" into the ports. So, I used a magnet to pull them back out again, and double checked the size of the plugs...yep...3/4". Only option I had was to try to shrink the port holes by staking them a bit, and using a ball-peen hammer on the plugs to flare them out a bit. It worked, as I them had to use a 9/16" deep socket to drive them all in. Then I staked them a bit more again so they don't move.
Yes, higher temperatures are better for gas mileage, emissions, and wear, and power to a point, but higher temperatures also make detonation more likely, and increase oil temperature as well, especially in hot weather. If you are positive that your carburetor jetting and ignition timing will be spot on, run your engine at the higher temperature if you like, but if your engine detonates at WOT, or your oil pressure is not sufficient for the RPM you are shifting at, you'll hurt it, that is for sure. All I am saying is be aware of the downside of higher coolant temperatures if you want maximum performance and intend to drive it that way.
You should be ok. Those crossover ports are tapered and kind of crude. I made brass plugs that are 1-1/2" by .750. Those taper down to .723 at the end to fill/stick out into the port area flush with rest of bowl. Ground them to the bowl contour after pressed in place. Also made short lightweight style that are .765 dia. to press fit in way down the port. Your stake job should work.
Those look great! I'll try to do something like that if we ever pull the heads off. Would like to go to the TA Performance aluminum heads, but still no definet answer as to when they will be ready to ship.
Well I didn't expect that kind of response. Was expecting more of do or don't kind of answer, but the response is still appreciated. If I can get freeze plugs that fit I will do it. After all it's not that difficult to remove the intake if I don't like the results. I just thought I'd do it because I had to replace gasket to resolve a vacuum leak. Thanks to all who replied.
If it's bone stock, don't bother blocking. You'll have to pop for new intake valley pan set and r&r the heavy iron intake, which isn't anyone's favorite thing to do, if you don't lIke the cold manners. :TU:
These engines were designed to run with 195* thermostats from the factory. Yes, their compression was lower than advertised, which made them just fine. You can bump compression and clean up combustion chamber to get similar results, only with more power, even better gas mileage, less emissions, and longer lasting oil using the same grade of fuel. Higher temps DO make detonation more likely, which is why you have to make sure you don't raise compression too much, while removing all potential hot spots within the OEM combustion chamber. I would say raising static to the advertised compression along with the combustion chamber cleanup should do the trick. I have written up a scale on dynamic compression to octane requirement, a rough estimation (and on the conservative side for safety), based on a 210* ambient environment. It considers mild engines with lower scavenging, which you would adjust upwards with more scavenging and VE flow. There will still be some leeway on your ignition timing this way. If the oiling is set up properly (booster plate and adjustable oil pressure regulator, which are easy to install), warmer oil shouldn't be a problem with oil pressure. I believe there are more upsides than downsides to running the engine as intended, even more so with modifications to improve the engine's efficiency. Exhaust manifold/header coatings that won't burn off is an excellent method of improving efficiency, not just from the exhaust's point of view, but for cooler ambient engine compartment temperatures. Simple tricks like this (among others) go a long way. It doesn't even have to be 100% stock either, as long as it's still relatively mild and has good intake vacuum. At least now I'm finally at the point where people are agreeing with me on the facts even if they do not wish to do this for themselves. People need to hear the whole truth, not just the hot rodder's point of view. Thank you, Larry. Gary Edit: here's the scale, along with an image from the internet (which I did not create) to give a visual representation for you graph lovers: Here's a rough estimate scale I comprised based on the Buick 350's open, yet smaller, combustion chamber. Though not as efficient as a closed chamber (quench), it is more efficient than a larger chamber (SBC/BBB, etc.) would be without quench. Dynamic Compression------Octane Requirement 6.0-6.5-------------------87 6.5-7.0-------------------89 7.0-7.5-------------------91 7.25-7.75------------------92 7.5-8.0-------------------93 These are figures based on sea level elevations. Adjust accordingly to variances, such as higher elevations, combustion chamber condition (such as untouched vs polished, etc.) timing location, light duty vs towing applications, thermostat temperature, etc. More ideal conditions will warrant compressions ranging on the higher end of the scale (I.E.- polished chambers, higher elevations, lower thermostat temps, etc.). Less than ideal conditions will warrant putting compression lower on the scale (I.E.- untouched chambers, advanced timing, stock thermostat, lower elevations, etc.). Most applications will live happily existing somewhere in the middle of the scale: Dynamic Compression------Octane Requirement ~6.25---------------------87 ~6.75---------------------89 ~7.25---------------------91 ~7.50---------------------92 ~7.75---------------------93 -GF My scale was based on 210*. Use the scale as a rough guide, and adjust up or down based on needs. I realize this isn't a magic bullet, but it at least gives a starting point reference. Gary
Nice scale does give a good rough idea. I would run synthetic oil also if I was going to run the higher temps on the motor, at least it does not burn and can take higher temps. I still say 185 is the best temp to use for all around diving. Soon as you start hot rodding it on the highway the temps will rise to 190+ Then at least at this point the engine will be able to cool off from 195-200 instead of 210-220*.
This post is no way intended to conflict with any information previously posted When you look at the graph (Vizard article, I believe), you see that just a little bit of water temperature is worth roughly 4 octane #'s...that's huge. That's only one metric. When you figure out how to maximize the effectivity of some other parameters you are now in a position to prioritize aspects of the operation of your engine. Basically, you are balancing the trade-off's and creeping up on diminishing returns in a controlled way. You can tip some of the scales far enough one way to intentionally negate some popularly held beliefs. One example is that on any of the high mpg builds I've done, I've seen negligible differences in mileage from water temperature reduction (in a certain range). Weather and air conditions CAN have a greater effect on that than water temps under some conditions, more so on the far ends of the scale. You will have the expected detriments...but you can play with those too...if you wish. I guess my whole point was to illustrate that you can get these things to do pretty much anything you want them to do. You don't have to follow the norm or have self imposed limitations based on stuff you read. With information sharing these days you (the average hobbyist) don't have to have a decades long learning curve anymore.
I'll disagree with a few points of course, but for the sake of clarity, it's more than just a little bit of coolant temperature that's worth 4 octane points. Some of your claims on here tend to be leaning toward the spectacular, and so could be why others have difficulty in believing some of it (as I've seen elsewhere). I know, you've built it all before and would have no reason to embellish anything. If you're intelligent, you don't need a decades long learning curve of trial and error either. Add to that things have been done by me for decades now, and you'll begin to see a larger picture, not just some words on a website. Your tone borderlines on the condescending, but it's neatly done and tactful at least.
I agree that temps somewhere between 185-215 is the 'ideal zone', and that cooler is easier to manage on a higher performance machine. In a more controlled (with less variables) environment such as OEM (or close to), going on the higher end of the scale is more efficient, and can be easily managed with an adequate cooling system, not one just borderline effective. When you start increasing power as with aftermarket parts, you begin to tax your cooling system's ability to effectively remove heat from the engine, and so starting off with a cooler thermostat can give one more leeway, particularly when the 'hot rodding' is limited to drag strip times or limited full throttle street use, when using the factory radiator. A properly functioning clutch fan along with a good (and properly placed) shroud goes a long way too. There's many factors to consider, and there is no one 'magic answer' for every application; there are, however, good guidelines to follow.
Not intended to come across as condescending, Gary. That's just the way I write. I probably come across different in person. I suppose it's difficult to use humor or any other communication techniques. I'm not a professional writer. I don't think anything I've posted is spectacular, maybe better than average in areas people don't normally play in. I've already stated that what I've "claimed" (as you say) doesn't even come close to what's already been done long before in various industries. Your issue with my posts seems to be based on an assumption that OEM engineers were giving us the best possible product they were capable of putting out and that anyone bettering the factory offerings must be truly outlandish. I strongly disagree with that. (That or maybe you think I'm a dick?) It isn't a bash on GM engineers, I think their goals are different than what marketing hype would have us believe. There are more experienced and better builders out there than myself. Most of the ones we really could learn from won't share the fruits of their education or offer up what might be considered competitive edge, they'll just ask you to "write the check". Others are bound by confidentiality agreements. With anybody's posts...I really don't refute what anyone claims as long as they appear to speak from having done it and not just reading about things. That's how we learn things. That's the point of information sharing, isn't it? The catch 22 here is that if a someone posts to a forum owned by a person in a related business and offers up too much "proof", it could be misconstrued as competition in the business. I'm really just encouraging people to try things and to educate themselves further. This conversation really should have been taken to PM's. I was attempting to post technical contributions, to be food for thought. It seems like I keep saying the same thing.
You can say one thing, then say your intentions were another, but the English language doesn't seem to be beyond either one of us, professional or not. I never claimed the OEMs were giving us the best they could, just that they were on the ball and gave us the best they could within the limitations that were placed upon them, which was still pretty damn good. I mean, we're all trying to improve things here, even me with OEM stuff. Working with the engineering intent instead of against it. That's been my premise all along here and in other threads. We all know the foundation (the stock engine) was impressive enough to want to improve upon to make even better, and I support making it the best it can be using the same intent that makes this engine so great. I appreciate your input. You have great advice and people can learn a lot from you. My real contention here is the 'one up' attitude you have with nearly every post you respond to (not just mine). I guess that's just your personality. I can adjust. Maybe it's just the way you present it, I dunno. Or maybe I'm just taking it the wrong way. I agree it can be difficult sometimes to discern humor in sentences without context surrounding it to indicate such, which is why I often use smiley faces or other emoticons to try to indicate when I'm joking (unless I feel the humor is obvious). We all share information about things, whether we've actually done it or just read about it somewhere, but the information I share is steeped in both research and experience. I apologize if it comes across as any different. I too encourage people to try different things, such as not ruining their engine by throwing parts at it others say are good, unless it's backed up with evidence/personal testimonies, etc. which I consider to be good enough. Knowledge comes from many sources. As far as this 'secret knowledge' you suggest at, it's not rocket science, and even if it was, can be figured out by someone with a brain. It's not complicated. I figured out more on my own than any other method, but I do learn from others. I've done more with camshaft science in a year than most of the others have doing it for a living for decades. I don't like to say this, as it will put up walls, but whatever. Don't hate me because I'm smart. There's more to it than seeing some letters or numbers on a paper, you have to see it in your mind, see the three dimensional activities of the dynamics in action. Some people can do this, while most cannot. While all this is fine and well, there's nothing like getting your hands dirty. I'm no stranger to this either. I have in fact worked on cars since I was old enough to hold a wrench, thanks to my Dad being an automotive tech. Always loved doing things with my hands. Building, creating, figuring something out. It's my bread and butter (literally). I just so happen to be book smart as well as hands on smart. So sue me :grin: I'll give you a little 'secret' about metal contouring: you have to 'feel' it, not just 'see' it. Fixing wrecked cars for insurance companies and restoring old cars, metal working, welding, grinding, molding, forming, it's all fun to me. I don't even consider it 'work'. I consider it art. Or maybe art married to science? Machining parts is always fun too. Calculating clearances and seeing it all come together is very rewarding. Need I go on? Some things cannot be learned in books. Or on websites. But we can do our best to describe things. Keep posting your technical contributions. I enjoy reading what you write. I always have. Peace bro. Gary
Yeah, this was getting weird, right? :Brow::laugh::laugh::beer Still trying to keep the comments not personal.
On the flip side I think there is more than enough knowledge in this thread to make an educated decision about plugging the heat crossover on an otherwise stock engine...and in the event that you should choose to make it a high performance engine you can surely see it benefits
It's nothing personal (well, maybe a little...). 8ad-f85, despite it all, I respect you. You have a beautiful mind and I thoroughly enjoy our dialog with your input on all topics. I'm not afraid to tell it as I see it, right or wrong. Keep up the good work, my evil twin! lol Is that creepy enough for ya? Derek, you're just jealous. :Brow:
