OK, if there has one thing that being a forum surfer has taught me over my brief tenure of being such, is there are a lot of things that affect, generate, hinder and enhance engine performance that are not understood or simply just ignored.
Most of this stuff is simply just not shared, be it that they are considered speed secrets or the lay person simply does not understand it, whatever.
I wanted to start a thread to discuss some factors that affect engine performance and the parameters that performance engines live within. Read, argue, whine or cry, this is the truth. And as Jack Nicholson said in "A Few Good Men"- "you can't handle the truth". Well, maybe you can, let's find out.
Get your calculators ready, over the next few weeks, you will need them.
Now, with all of that out of the way, let's start by nailing down the first thing we need to consider when wanting to build a new engine and get the maximum performance out of it. Knowing what we want to use it for will deliver the best possible results. Building a high strung engine to take the family to picnics on Sundays will probably not deliver the experience you are after. Well, maybe the experience you are after, but probably not everyone else in the car.
The best place to build a starting point is to determine intended purpose of our engine and then correlate this to a range of piston speeds.
Piston speed will have a crazy-huge effect on how the engine performs.
I am going to break this down into different categories. For those of you playing along at home, I will give you several examples to experiment with, I am not going to lead you down a primrose path to a result that I have predetermined. Your rules, build what you want without spending a dime.
OK, the categories are:
Street engines (stock)
Mild performance or street/strip
Endurance/NASCAR/Road Race
Maximum effort (Mileage limited/drag race)
AYFKM effort (Component failure limited)
Now, the classification for each of these categories are split by how fast we fling the piston. But first, I guess we need to know how to determine piston speed so we can then determine which category we belong in, or vice versa.
The formula for Mean Piston Speed (MPS) is MPS in ft per minute=(inches of crankshaft stroke x (engine RPM/6))
Depending on the stroke of the crankshaft, and the RPM you expect to see, we can categorize our engine. This will affect our pocketbook, because it will directly affect the type and quality of parts we need to buy to support our performance objectives.
Now let's put these categories in a manner where piston speed can help us determine what we are building. Or, what we need to build to fit into a certain performance category.
Street engines (stock) 2000 to 3000 ft/min
Mild performance or street/strip 3000 to 4000 ft/min
Endurance/NASCAR/Road Race 4000 to 5000 ft/min
Maximum effort (Mileage limited/pro class drag race) 5000 to 6000 ft/min
AYFKM effort (Component failure limited) 6000 to 7500+ ft/min
OK, so if you tried a few different combinations, you probably realize we can change the category by solely changing the stroke, changing our RPM, or both. So great, wow, what a speed secret. Thanks a whole pantload Parker, I read through all of this for that? You're an asshole. Yeah, I know I am, thanks. But the thing that we need to understand about the formula is you need to understand engine speed (RPM) is power. Let's take a look at two theoretical engines and another formula, this one you have probably seen.
Horsepower = (Torque x RPM)/5252
By solely changing RPM, I can make one of these engines a grocery getter and the other, an F1 contender.
Two little six cylinders; both make an eyeball popping 246 pound feet of torque :lol
In the first one, my maximum usable RPM is 4500, and when plugged into the above formula (go ahead and do it, doofus), we see the engine is capable of making about 210 horsepower. :facepalm:
Now we will leave everything the same as far as torque, but let's give the engine an F1 race car caliber RPM of 19,250. After you do the math (I don't have to call you doofus this time, do I?) we see that though my torque stayed 246 lb/ft, my horsepower climbed to a panty-dropping 910! :willy
RPM is power folks, RPM is the shit. RPM can also stand for "Ruins People's Motors" if you don't know how to handle your newfound knowledge.
Piston action has a dramatic effect in the way air and fuel enter, and exhaust leaves the engine. Going back to our categories, we are going to relate the effectiveness of this piston action with our engine and piston speed categories. We do this using something called Volumetric Efficiency, or VE. VE simply put is; if I have a 100 cubic inch engine, and that engine can breathe in and expel 100 cubic inches of air for every camshaft (two crankshaft) revolution(s), it is 100 percent volumetric efficient. If the design of the heads, intake and exhaust only allow 85 cubic inches of airflow through the engine, it is 85% volumetric efficient. If it can move 110 cubic inches of air flow, then it is 110% volumetric efficient. Are engines over 100% VE possible? Why yes, yes they are, and I am going to show you how to build one. Wow, a 350 cubic inch engine that can move 385 cubic inches worth of airflow? Oh yes, yes indeed.
But that will wait until the next installment, for now, let this digest.
Street engines (stock) 2000 to 3000 ft/min 80-90% VE
Mild performance or street/strip 3000 to 4000 ft/min 90-110% VE
Endurance/NASCAR/Road Race 4000 to 5000 ft/min 110-120% VE
Maximum effort (Mileage limited/pro class drag race) 5000 to 6000 ft/min 120 to 127% VE
AYFKM effort (Component failure limited) 6000 to 7500+ ft/min 125 to 128% VE
So we have learned that how fast the piston moves has a great affect on the performance I can expect. And we also learned that piston speed is primarily controlled by the stroke of the crankshaft and the RPM of the engine. We also see how changing piston speed makes my engine fall into different performance categories.
Next time I will give you some real world examples I have tuned on the engine dyno and tested on the drag strip, as well as begin to talk about hw we get the air into the engine to take advantage of all of this piston speed we just talked about.
Cheers, Parker
Listen if it’s a Corvette and you want to make it go faster…I’m fine with that. Who cares, why you want to make it go faster?
From http://www.corvetteonline.com
What would possess someone to create a Corvette with over 2,200 horsepower? Does it really matter? With an amazing feat like that, we didn’t think so. Take a look at the unbelievable Top Speed C5 Z06 that has over three times the amount of horsepower as a modern ZR1 at the April Ohio Mile event in the Wyldfantasies Media Studios video above.
Built by Hinson Motorsports, “Record Hunter” is among the most powerful Corvettes we’ve ever seen and there’s reason for that. Bringing the car to its astounding 2,246 HP rating at 7,800 RPM is a massive build the crew completed back in March.
Under the car’s hood you’ll find a 427 cubic inch RHS Aluminum Tall Deck Block assembled and machined by Butler Performance. Stuffed inside this block are aluminum connecting rods, Diamond pistons and a Callies Ultra Center Counter Weight Billet Camshaft, as well as a custom high capacity oil pan from Doug Lee Engineuity.
Making up the engine’s top end are TEA-ported Trick Flow 245cc heads, Crower roller rocker arms, COMP Cam pushrods, a custom COMP solid roller camshaft and a GM EFI carb-style intake manifold. But these components alone aren’t what gives Record Hunter its massive amount of horsepower.
That extra boost comes from an intricate custom turbocharger system featuring a 118mm turbo, custom air to water intercooler, Tial wastegate and blow off valves, and a 5-inch downpipe all working to the tune of 34 PSI manifold pressure.
Of course, a build like this makes for extra fuel needs, which the team has dialed in using a Holley Dominator EFI system and Bosch 160 pound-per-hour injectors, as well as a regulator and fuel pumps from Fuelab.
The whole build is backed by a RPM-built TR6060 transmission with a SPEC twin disc clutch and an RPM ZR1 differential with Quaife LSD.
Surprisingly, the Corvette looks relatively like the C5 production car it started out as, minus the modified hood, roll cage and custom adjustable rear wing, of course. But obviously, looks can be deceiving. And 18-inch wheels from True Forged Wheels wrapped in Hoosier R6 rubber make sure that as much of Record Hunter’s power as possible is delivered successfully to the ground to turn heads like no other C5 can do.
After completing the build in March, the Hinson Motorsports crew took Record Hunter to the Ohio Mile, an East Coast Timing Association event in Wilmington, Ohio on April 29th to see what it could do. As the first standing mile event the Corvette raced at since its build, the April Ohio Mile proved to be a great tuning opportunity for the crew since the mile race was speed-limited to 150 MPH.
It may not look too far off from stock, but Record Hunter packs nearly 2,000 more horsepower than a stock C5 Z06.
As the car’s name suggests, future goals for Record Hunter are to set new standing mile records. With a car potentially capable of topping out at over 250 MPH, we’re sure Hinson Motorsports will be making history with the car this season. Be sure to watch out for Record Hunter at any of the standing mile events this year. To check out some in-car footage of the first standing mile pass the Corvette did since its build, watch the video below.
It’s nearing the peak of summer, which means 2013 model year cars are only weeks away from being released. But before we can welcome in the last of the C6 models for next year, we owe it to the 2012′s to take a look back and see just how well the Corvette did this year. So here are some of the production numbers for the Corvette’s 2012 model year compliments of CorvetteBlogger, and some of them may just surprise you.
Just like in the 2010 and 2011 model years, the Grand Sport got the most amount of buys for 2012. Between the Grand Sport coupe (5,056 sold) and the GS convertible (2,268 sold) , the model made up nearly 63 percent of all Corvette sales. Coming in at a far second, was the base model with 2,820 coupes and just 651 convertibles sold to make up 29.5 percent of Corvette sales.
As far as the high-rolling Z06 and ZR1′s go, only 478 Z06 models were sold, making up 4.1 percent of total sales, and only a measly 404 ZR1′s were sold, making up just 3.5 percent of sales. In total, 11,647 Corvettes were manufactured for the 2012 model year.
Not surprisingly, the most popular color among the 2012 models was Torch Red with 19.5 percent of Corvettes sold sporting the color. The vibrant shade was closely followed by the Carbon Flash Metallic paint of the special Centennial Edition cars. Nearly 19 percent of Corvettes sold featured the special edition package.
Other interesting tidbits we found browsing through the 2012 production numbers were that 62.3 percent of Corvettes were sold with Ebony interiors while only 88 were sold with yellow stitching accents and 105 sold with blue stitching accents.
Option packages appear to have been popular with 2,416 Corvettes sold with the 1LT option package, 1,691 sold with the 2LT package, and 5,510, or 47.3 percent, sold with the 3LT package.
For more of the 2012 model year numbers, check out the full report from CorvetteBlogger.com.
No this isn’t going to be one of those talks and no we aren’t going to run out and hung a tree, ok…if you must…go ahead I’ll wait…..(insert bored whistling)……(more bored whistling)…..Ok…are you done?!!
As I get closer to getting the heads on the Mustang, I’m going to have to begin picking any changes I want made to the CJ heads. While cruising the web checking out options, I ran across this piece (Corvette related but springs are springs as far as an engine is concerned) and there are some good tips here.
Quick! What the fastest moving component in your engine? If you’ve taken a hint from the title of this article, you probably guessed correctly – it’s your valve springs, those tight little bundles of joy that open and close your engine’s valves.
Beehive springs come in a variety of shapes and sizes. The benefits of moving to Beehive springs where possible (and today few situations are not Beehive compatible) are many.
Beehive springs, such as those offered by COMP Cams, offer a huge number of benefits over stock-style cylindrical springs; reduced valve spring mass, faster valve acceleration, increased valve train rigidity, reduced valve train component stress and a whole laundry list of other positives.
Best of all, the word has gotten out and folks all over the country are using them for a wide variety of applications from street performance to extreme racing endeavors. That’s a really good thing.
Along with their success has come some confusion over exactly which beehive is right to purchase. Currently there are over a dozen beehive spring styles out there, each offering some unique take, be it in the seat pocket diameter, ovate wiring diameter, pitch or internal spring “frequency.” Regardless increased selection has bred some minor confusion, albeit easily cured.
Beehive springs are conical shaped springs that employ this powerful shape in the creation of a spring that can deliver both excellent performance and lowered seat pressures. With lower seat pressure, valve train components (especially the pushrods, rockers and lifters) are less stressed to perform the same work.
This beehive spring weights in at 99 grams, while a comparable conventional spring is 121 grams.
The difference between beehive and conventional cylindrical springs is obvious especially when you compare them in this manner. Note the dramatic difference in retainer diameter equating to less valve train weight.
According to COMP, effective beehive springs can support an additional 700rpm over stock cylindrical springs. How? It just stands to reason that the smaller coils at the top of the spring don’t require as much force to get the valve moving quickly, much quicker than conventional style springs. The higher rpm potential equates to better durability and performance.
There are some very knowledgeable engine builders who don’t understand how a single coil spring can be better than a dual conventional spring.
“Its like watching a race car running 60-foot elapsed times on the drag strip,” stated Bill Godbold, Chief Engineer for COMP Cams. “For example, take two identical cars with equivalent 500 hp engines.
“One has stock suspension and the other a sophisticated racing suspension. The car with the race suspension will get going more quickly and achieves better 60-foot time. The same principle works with beehive spring mechanics.”
I ran across on ton http://www.corvettereport.com and thought I pass it along. If only they made some of these!!! You got to check out the 1991 C4 body.
Hot rodder Shinoda teams up with Bill Mitchell and defined the “Corvette look.”
Perhaps it was “in the stars” that Larry Shinoda was in the right place at the right time. If you strictly look at Shinoda’s resume in 1956, you might ask, “How did this guy get in the front door?” As a young man, the only thing Larry ever graduated from was high school, Army boot camp, and the School of Hard Knocks. Twelve-year-old Larry had his life turned inside out when along with thousands of Japanese-Americans, he and his family were sent to interment camps for the duration of WW II. The experience had a profound effect on his personality. A self-professed “malcontent” Shinoda could be a little difficult to work with.
After his Army tour of duty in Korea, Shinoda attended Art Center School of Design in Los Angeles, but truly hated being there. He could see no purpose in taking the classes in design and the various art mediums, such as watercolor painting. He was a car guy/hot rodder and he wanted to draw and design cars! So he left Art Center without graduating and based strictly on his car illustrations, landed a job at Ford, then Studebaker/Packard. Just a year after starting his career, he landed a job as a designer at General Motors.
The rest is the stuff of legend. Street racing and blowing the doors off of Bill Mitchell’s souped up Buick and quickly being taken under Mitchell’s wing. Things like that happens, but rarely. There was obviously some chemistry between the two men, perhaps it was because both men could be brash and had strong opinions.
Shinoda got his first big break when Mitchell tapped the 28-year-old to translate the body design of the ‘57 Q-Corvette on to the mule chassis from Duntov’s aborted Corvette SS project. The finished car became Mitchell’s 1959 Stingray Racer, which formed the styling theme for the ‘63 Corvette. From there, Shinoda got one peach project after another. It’s worth noting that the design of the Stingray Racer is held in such high esteem that current Corvette chief designer, Tom Peters (C6 Corvette and late model Camaro designer) is on record stating that his ‘09 Corvette Stingray Concept (aka Transformers Corvette) was influenced by the ‘59 Stingray.
During his almost 13 years at GM, Larry designed numerous special Corvettes, Corvairs, and several race cars, as well as his usual duties working out the styling details of various production cars. Presented here are Larry Shinoda’s most important Corvette designs. Later this week, we’ll take a look at Larry’s very slick Corvairs, and race cars, including the body design for Pat Flaherty’s 1956 Indy 500-winning Watson-Offenhauser.– Scott
1959 Stingray Racer The 1959 Stingray Racer is still a stunningly beautiful car design. The idea of a “broad, flat top surface” was to create a reverse airfoil that would pull the car down. The problem was that the sharp leading edge was too high and at high speed, more air was knifing under the car rather than going over the car, causing a serious front lift problem. The production Sting Rays and even the Grand Sport Corvettes all had the same trouble. This could have been corrected with a slight forward rake, if the nose had drooped down a n inch or so, and a chin spoiled was added. The Grand Sport replica cars from Duntov Motors use these corrections and front end stays where it belongs at high speed – DOWN.
1963 Sting Ray Concept Art The road to fully worked out new car designs was littered with concept art – most of which was probably thrown away. Here we see a headlight treatment study. Sorting out the production car’s rotating hidden-headlight design was a brilliant but challenging project. Note the absence of hood lines and windshield wipers. It also looks like they were considering scoops on the back edge of the doors.
1961 Mako Shark I Showcar – AKA “The Corvette Shark”
With the basic Sting Ray design approved for production, Bill Mitchell had Shinoda design an exaggerated version for a teaser show car. Known today as the Mako Shark-I, the car’s original name was simply, “Corvette Shark.” 1961 was still the “Jet Age,” so the car was originally shown with a plexi bubble top. It was kind of “Jetsons” neat-looking, but would anyone really want one for their daily driver?
1963 4-Seater Sting Ray Split-Window Coupe
The XP-720 4-Seater Corvette Sting Ray was an exploration into the possibility of the Corvette competing with the much better-selling Ford Thunderbird. Ed Cole, head of the GM car and truck group, thought it was a pretty good idea. After all, GM is in the business of selling cars – LOTS of cars. Since the public bought 73,051 Thunderbirds in 1961, compared to 10, 939 Corvettes, it seemed like a no-brainer. The story goes that a tall executive got stuck in the back seat and needed quite a bit of help getting out. The 4-seater concept was quickly dropped. Good!
1963 Production Corvette Sting Ray Split-Window Coupe
Look at 1963 cars from America and Europe and there’s NOTHING like the Corvete Sting Ray. The split-window was one of Bill Mitchell’s pet design elements and was a one year deal. Although the design concept of a “split rear window” wasn’t new with the Sting Ray (the 1950 VW Beetle had a “split” rear window), the overall presentation of the Split-Window Coupe Sting Ray looked like NOTHING else.
1964 XP-819 Rear-Engine Corvette Engineering Study
The Corvair was the only production car to come out of Ed Cole’s ‘57 Q-Chevrolet initiative and was considered very exotic when it came out in 1960. But trouble quickly set in and it wasn’t just Ralph Nader’s doing. The early Corvairs were not good cars. But the “rear-engine” concept was very alluring to Chevy engineer Frank Winchell. Frank insisted that with the correct size tires the inherent oversteering problem could be corrected. Winchell envisioned a rear-engine Corvette and Zora Duntov said, “No!” To prove his point, Winchell had Shinoda design a pretty body to cover the big V8 engine hanging out behind the trans-axle. Upon seeing Shinoda’s rough full-size drawing, Duntov asked, “Where did you cheat?” Where he cheated was that there were no real rear bumpers or crash zone on the back end. The concept was quickly dropped. it was also discovered that the car did excellent wheelies!
1966 Running Mako Shark-II Showcar
Bill Mitchell verbalized the parameters of the design and Larry Shinoda and a small group of designers and stylists worked out the details. It was as if lightning had struck twice – first with the Sting Ray and a few years later with the Mako Shark-II. The exaggerated fender humps have become THE signature Corvette profile. A non-running full-size version was shown to GM’s management in ‘65 and received unanimous approval as the next Corvette. While the new body and interior designs were being worked out, a second “running” Mako Shark-II was built to keep the Corvette fans stoked. Almost 50 years later, the Mako Shark-II is still a jaw-dropper!
1991 Mears-Shinoda C4 Corvette Body Kit
Larry left GM in 1968, stayed at Ford for one year, then formed his own design studio where he worked on all kinds of automotive and non-automotive design projects. Corvette body kits and add-on parts became very popular though the ‘70s and ‘80s. Three-time Indy 500 winner, Rick Mears teamed up with Shinoda and businessman Jim Williams in 1991 to create and offer the Rick Mears Special Edition Corvette.
Arguably the cleanest full-body-kit ever offered for a C4 Corvete, the coupe version lowered the coefficient of drag on the car from .34 to .30. The complete kit cost approximately $5,200, plus $3,000 for installation, and around $1,000 for a new paint job. With a cost of just over 10 grand on top of a $32,455 new ‘91 Corvette, there weren’t many takers. But, it was a very nice design.
Shinoda C5 Sting Ray Concept
The all-new C5 1997 Corvette was released in the Fall of ‘96 and Larry Shinoda got right on it. Note the date on the rendering, “1-6-97.” Obviously, Larry wanted to see more “Sting Ray” in the new C5. If you’re a mid-year Corvette fan, Shinoda’s concept looks pretty good. Larry died the following November and to the best of my knowing, there was never an effort to make a full-body kit based on what may well have been Larry’s last Corvette design project. Any fiberglass fabricators out there that would like to take a shot at the Shinoda C5 Sting Ray???
No it’s not real Corvette – but the Collector’s Promo Revell Model. In the original box.
All you have to do is guess the year of the Corvette the part pictured belongs too!!! First one to post the answer gets 1 point. The first one that gets 4 correct wins the car.
No it’s not real Corvette – but the Collector’s Promo Revell Model. In the original box.
All you have to do is guess the year of the Corvette the part pictured belongs too!!! First one to post the answer gets 1 point. The first one that gets 4 correct wins the car.
WOW…I apologize for leaving you hanging for so long without finishing this interview.
Here is the link for Part I.
So while at first glance it did appear that there were just newly built vintage shaped bodies, placed on the C6 chassis, a really close look and you can see something very different about the shape.
The door is clearly still a C6 and the windshield is C6.
So you can tell that they didn’t just pull off that old C6 body and dump it out behind the barn.
You can tell this is the original C6 hatch. The rear end is has been changed but where the hatch meets the roof line is the same.
So how do they do it?
Well the make body panels that fit to the framework of the exiting parts. For instance, the rear hatch is striped of the outer panels leaving just the framework and the split window panels are fitted. The rear panel is pulled off and the rear panel with the split bumpers is placed on.
Jim showed me the shop photos of a C6 – skinned. They also retrofit C5.
C5 Rear hatch frame. The split window panel is manufactured by Karl's Kustoms to snap right on.
It is a pretty intense process.
They all the do is custom bodies? Oh wait until you see what’s next. (Yes I promise I’ll get right to it.)
When I first purchased my 07 Corvette and took my wife for a ride. I was pretty jazzed and noticed the noise emanating from the roof.
That was the first thing she noticed. I was so caught up in the handling and power I was ok with the noise. But after she mentioned it, I wasn’t able to ignore it quite as easily.
The squeaking was very profound and since our roads aren’t the best in the land, it crazy loud. So the search was on for a cure.
Lots of help on-line including resetting (releasing the front latches) and closing them again. This came with the sage advice “….I got the wife accustomed to helping me reset the top at stop lights…don’t do it while you are moving….” I wonder if that little nugget was from a first person experience?
And for a while I would reset the top latches (not while moving) when the noise got frequent. But that just couldn’t be a long-term solution……”ERRRRRKK….(braking noise)…..I brake for “soap boxes”!!!
I am frankly sick and tired of hearing for Corvette owners the following phrases…”that’s the nature of the beast”….”that’s just something you have to live with”…and the my favorite…”You’ll get use to it.” That is all BS. If things are broken…then they are broken. If doesn’t work like it’s supposed to, then it needs attention. I’ve heard that ever since I’ve owned my C6. Those tired phrases, were used for the squeaking roof and the odd activity with my gas gauge after filling it up and the cold weather shifting issue. No way dawg, I want this stuff fixed!!! .
So back to top issue. After checking with a few more Corvette buddies, I ran into to one that gave me this, every valuable tip. He used it successfully.
Get out the lube…Dielectric grease the rollers / contact point for the front latches and the pins in the back. Lube up the rubber moldings /contact points of the moldings.
Di-Electric-Grease
Lube the rear posts.
Spray a little on a rag and wipe down the rubber weather-stripping. You don’t need a lot.
I’ve only done one time and not since. But I keep the rubber clean and no problems.
For those of you aren’t familiar with the top (I’ve talked to a couple that didn’t know the coupe had a removal top.) see the video below.
