engine. It's amazing how people look for "YOU" by word of mouth and wanna do a write up on your stuff. I had a brief stint on the blow-thru carb builds as well, not much but it was mentioned. Jason is one hellava guy and if you ever get a chance to check out his yellow GT that Dave Zimmerman (Team Z) built, check it out. My engine builder Dan Rawls gave Jason the finer engine details and while talking to Jason last night, I was able to give him a few more details. I also mentioned all my homies here at theturboforums for all their hard efforts and work making headway with blow-thru cars as well.

Here's part one of what Jason wrote. Part two has pictures and such of the engine.

There are many misconceptions throughout the performance world, but the performance of a carburetor-equipped hot-rod should not be one of them. Over the last several years, we have seen debates online on various different forums as to which type of combination will make more power, a carburetor or a fuel-injection setup. We have heard of people running them back-to-back on the dyno, and the carburetor almost always comes out on top, no matter how good the fuel-injection tuning is. There are many reasons for that, chief among them that the carburetor will always do a better job of atomizing the fuel than a fuel injector will. Why, you ask? Good question '“ and the answer is that the carburetor relies on the vacuum signal from the engine to suck the fuel from the carb, which helps it to do an outstanding job of atomizing the fuel and placing it into suspension with the incoming air to the engine. Fuel injection, on the other hand, relies on the injectors to place the fuel into the intake runner directly next to the cylinder head port, which doesn't allow the air enough time to disperse the fuel and help it to become a mist, which is what helps the carburetor-equipped combination to burn the fuel more completely and make more power as a result.
With that taken into account, Brent Davis decided to build a blow-through, 427-cubic-inch, twin-turbo '˜street car', using Dan Rawls and David Powell at Cleveland Performance to screw the beast together. Dan and Dave have years of experience building engines, as they put Brian Mitchell onto the podium to accept three EFI Renegade championships over the years, and Dan himself finished second in EFI Renegade points this season, while Mitchell finished fifth in points. Davis and Rawls have been friends for a few years, and when it came time to replace the current Cleveland Performance powerplant in the car, he knew exactly where he was going. The old powerplant made 1177 at the tires, but had major traction issues and got a best ET of 10.02 but at 170 MPH, therefore Davis was never able to get the times out of it that he wanted. With those issues in mind, he realized that it was time to upgrade the rest of the car to match the performance, and it was off to the chassis shop for some upgrades. Back when he first got involved in the sport, and much out of necessity, Davis started modifying his own carburetors in order to get the performance he was looking for, and has become quite successful at doing that over the years. Combining his experience with Rawls', after their first successful build together, seemed like a natural fit.

Details, please?
The engine build, while it will be boosted by a pair of 76mm turbochargers, really isn't nearly as advanced as you might think it would be. While the turbochargers will easily support 2000 horsepower, Davis isn't looking for that, so they will be turned down to provide enough power to put 1600 up on the dyno needle, according to Rawls. And the combination? We thought you'd never ask. Davis was successful with the Trick Flow '˜High Port' cylinder heads that were on the old engine, so they have been pressed back into service on the new one, albeit with a little bit more port work. A Dart Iron Eagle block, bored to 4.125', provides the foundation for the bullet, and Davis selected a Scat forged-steel crankshaft, and Scat forged-steel connecting rods to go along with them. The main change comes in the piston design '“ Rawls has been working with Ross Pistons for years, and selected one of their high-strength '˜turbo' forgings to compress the air/fuel mixture. We were curious as to the use of the steel connecting rods in such a high-horsepower application, but according to Rawls, it's much like the build of our own project car, the Bionic Banana. The ring package has been selected with the boost in mind, and it includes an AP-style steel top ring, Napier-style ductile iron second ring, and a CP20 oil ring. Since Davis will be using a vacuum pump, the corresponding hone job on the cylinders and the rings themselves have been specified with this in mind.
There are a few tricks that Rawls has employed to make sure that this piece lives through whatever Davis throws at it, and one of them is in the piston pin design. Over the years, Rawls has found that one of the biggest issues in a boosted engine is pin rigidity, and the .220-wall, tool-steel pin design is the culmination of that research. 'We're going to use a hydraulic roller camshaft in this engine, just like we did in Brent's last one, supplied by Bullet Camshafts. We've had great success with their camshafts over the years, and since we're not going to be seeing a lot of engine speed in this engine, it will be perfect. All of the valvetrain pieces are compatible with this. The old engine made almost 1200 at the tire with the hydraulic roller camshaft. We don't use a ton of lift in an application like this, and although the ramp speed is a little bit aggressive, it's only a little over .600 lift. The cylinder head ports are designed all around that, and there's no problem at all to run 7000RPM. Where you start to need the solid roller camshafts is when you start to turn it up around 8000RPM. Of course, this engine doesn't have the same type of light valvetrain that we run in the Renegade engines, but it all still functions the same way. It's in the same range as the Renegade engines, though - you can control the oil in the lifter, and keep the pushrod from flexing. We do use a Jesel shaft rocker system in this engine, and works well to help us control the valvetrain. Unless everything is right, you shouldn't be turning the engine over 8000 with the hydraulic roller anyway, and we have the experience to make it work properly,' says Rawls. One of the things that we were curious about, but Rawls would only touch on, was how to get the valvesprings to work in an application like this. Obviously, we understand that he doesn't want to give away the trade secrets he's worked so hard to discover, but he did tell us, 'The main thing in a boosted engine with a hydraulic roller, you have to find the point where you need to valvespring it '“ as you add boost, you have to be able to control the valve. With the boost constantly pushing on the back of the intake valve, you have to find the happy medium where everything works together. We've got a pretty good handle on all of that stuff. As long as you have enough hydraulic clearance for the ramp, you'll be fine.'
With that being said, the engine is a pretty basic buildup for the amount of power it's going to make. Rawls tells us that he's never had any issues with needing oil restrictors in an engine running at this engine speed, so they are using a Melling-style race pump to supply the oil to the top end, and keep the bearings lubricated as necessary. To go along with those Trick Flow heads that have worked so well, Rawls ported an Edelbrock Super Victor carbureted-style intake, and Davis will be topping off the whole works with one of his own modified carburetors. According to Rawls, 'Brent has developed a neat blow-through carburetor that he sells, in addition to using it on his own car. It has a secondary pump to aid in drivability, which also allows you to take some of the mixture out of it that you might see during transitional points of throttle application. To people that have never driven a blow-through boosted engine, whether it's turbocharged or supercharged, they don't realize that the drivability rivals the very best fuel-injected cars out there. We do quite a lot of them down here. For one thing, it's much cheaper to put one together, and it's simpler for the average guy to put together. In many cases, the carburetor will make more power also.'
Another interesting point that Rawls raised during our conversation about the engine build was the tidbit that Davis wasn't even going to be using an intercooler in this car. Inlet temperatures on a blow-through application are much lower than your typical fuel-injected cars, and the reason becomes quite simple when you step back and look at the issue from the outside. 'The average inlet temps are between 140 and 150 degrees, but the fuel in the manifold absorbs the latent heat, whereas an EFI manifold only has the air coming in '“ there's nothing to pull the heat away until you get to the cylinder head where the injectors are placed. There is also less friction in the manifold from the air flowing over it in this application.' According to Rawls, the injector doesn't do anywhere near the job that a carburetor does. He stated that the smaller the fuel droplet is, the better it can help to absorb that heat from the turbochargers, and we're inclined to agree. Using science to make a car go faster '“ wouldn't you have paid more attention in high school if you had known?

 

Very nice, Outstanding write up Brent! Jason is a very cool guy.

Also good write up for Dan and Team at Cleveland Performance.

 

Awesome! Great article for everyone!!!

 

congrats Brent... Is he doing a write up on your carbs as well?


Jeremy

 

Thanks Tim and Ken.

Jeremy, no need for carb build write up. It was an article that he really wanted to do about the engine with minor details thereafter.

 

Very cool Brent. I bet it feels good to be recognized like that. That was a good read.

 

Thanks Tim but it was more of an article that Jason was looking to write on an engine and my 427 just so happen to be sitting there at Dan's shop. Jason really like Brian Mitchell and Dan and wanted to give them some advertising sorta speak and my stuff just happen to be around. Your car is looking absolutely great. Good luck to all on the 2010 season.

 

Maybe so, but it takes vision & patience to build a car like you have.... And by the end of next year (if I can speak for some of the members on here), were fully expecting to see your car dip into the 9's pushing 200 MPH. LOL

 

Not sure he can handle that kind of ET. The man loves his MPH, I am starting to think he is afraid of the ET

Ok, what ever you say. Still very cool to see your name in print.

 

This coming from someone letting out at the 1000' 'cause he was getting scared going over 150...... <cough> Tim <cough>

That is funny though, you go Brent!

Craig

 

LMAO. True, so true.

What out there now.

LOL. Hey man it does get pretty damn scary up there IMO but 150 is not my breaking point.

 

I admit it; that was me a couple years ago :scared: but see that was in the 1/4.... 150 in the 1/8 isn't as fast as 150 in the 1/4

 

Just had to poke at ya a little bit there buddy. You'll be running in the 7's with no sweat next year!

Craig

 

Congrats Brent nice article,That thing is going to be a Beast!!!!Get some pics up soon!!

 

Curious, why ditch the IC ? Worked really well for ya didn't it ?

 

that is a nice article. what chassis work are you getting done? just the cage so you can run the times? 1600hp, damn. I've always been impressed by your car with the small block and cited your combo in many conversations to tell people how good turbos+carbs work.

 

Very nice Brent .

Cant wait to see it run .

 

I am not sure where that came from and I told Jason that was not true and that I am indeed keeping the intercooler.

Thanks Randy. It was only after you and I hooked up with building your carb and seeing the results and a much lower boost level that I was using in my 302 that I decided to go with a 427 but with the twins and that is mostly because the packaging is easier with the tubing and such. I'll holla at you later this week brutha. You've helped me a ton with these decisions .

Thanks dug. I did and still do like the smaller motors hence Big Daddy running well over 200 MPH and now in the 6's with a 390 inch twin 88mm turbo going up against BBC motors and F3 blowers and even twin 88+ turbos. The 302 worked extremely well but I know that the 427 will not need as much boost to make the same 1200 HP. Blow-thrus don't work, didn't you know that .

Thanks Dave. You've been an inspiration as well and once we hooked up on the metering blocks, your results just added to the knowledge of what I am doing indeed works. I have a 850 DP to start with but will also build a Dominator using the "CRUTCH" for a complete dyno comparison. Keep up your great none working blow-thru tests too.

 

Awesome Brent, cant wait to see it all together! That boost # will definitly come way down for the same hp the other motor made!

 

Very cool Brent, nice write up. Congrats!

So this will be a "to be continued" article then right? The next installation in the mag will be the trip to the chassis shop.

If your at work (like me) and Yellow Bullet is blocked, you can read more about Jason's car here http://www.nmradigital.com/forums/showthread.php?t=45975 It's an awesome build and I got to give her the name!