Chris McGaha doesn’t hold anything back. He speaks from the heart and tells it like it is, so when we delved into the intricacies of Pro Stock racing in 2016 for the first year of fuel injection, we got much more than we asked for. Chris has been racing in Pro Stock for four years, having come from a Competition Eliminator background with his dad’s car in the 1980s. As he says, “When I was nine, I thought everybody had a C/Econo dragster with a 750 on it.” Amazingly, in this age of super-sponsors, his family business pays for the majority of the racing expenses. Why? Because they’ve always wanted to be competitive in Pro Stock—and they are. For 2016, Chris and his Harlow Sammons Racing Camaro was seventh in NHRA Pro Stock points in a season completely dominated by Jason Line and Greg Anderson. He does all of his engine development and also builds engines for Mopar’s Deric Kramer, who came in 13th in 2016, so he’s deep into both GM and Dodge engine platforms. As a privateer, he wound up ahead of the entire Dodge-sponsored operation. He knows stuff and is willing to share just enough of his knowledge to make you understand that Pro Stock is an arcane, difficult pursuit. Says Chris, “Some of the things you do to chase one-one-hundredth of a second, you’ll go out on a limb and suffer a lot of defeat for that.” So we were curious. There are so many rumors and misunderstandings about the secret world of Pro Stock that we asked what we could, and Chris answered almost all of the questions posed to him. Almost.
If you don’t cheat, you have to learn to think like some people that cheat so you can at least call them out on it” — Chris McGaha
HRM] Have you been able to get past the firewall on the Holley ECU?
CM] [Sighs.] I know one team has the ability to do it because they have the guy that is the grandfather behind all of this; he wrote the book on aftermarket EFI, but most teams have too much to lose if they get caught.
HRM] Would you like to see the 10,500-rpm mandated cap raised?
CM] 10-5 was the number they got after all of the software and firmware was lined up, but it’s more realistically at 10,580 rpm. I’ve seen some 10,620 rpm myself, but I’ve also seen that with the same computer on the same weekend, it was at [10]590. Then on the next run, it jumps to [10]620. Sometimes you press it to see, and it will take it, and then the next time it won’t. I have the two-step turned off up there [in the high rpm ranges].
HRM] It seems some drivers hit the rev limiter before the lights. Is this some sort of strategy or advantage?
CM] The reason you do it is because of the gearing. You don’t make power at 11-3 or 11-4. It goes back to your fallback—what do you fall back on for a gear change? So you try to control that and hit as high an rpm as you can. That’s why the rpm got higher overall. The Dodges had to do that. They set the pace because they didn’t make the torque, yet 400 to 500 rpm above a Chevy they start to make the same power. So when you’ve done everything you can, do you go out on a limb? You have a gear in the back and it’s crossing at 10,520 rpm, but putting in a different ratio gear, you might cross at 10,620 rpm. Putting different tires on you see if it crosses 75 rpm higher. Change our transmission and then from the start to the eighth-mile it changes our splits and the fallback, so by half-track we get enough to pick the car up. Then at the lights, you’ll hear us on the chip. When we didn’t have the limiter, we knew we had enough room—we didn’t care if it crossed 100 rpm higher. It might hurt a couple of valvesprings, but it’s what you did to go an extra hundredth of a second faster. We were pressing the envelope, but nobody knew that because we would move the chip up.
HRM] The DRCE2 block used for more than a decade in Pro Stock seems to be the most popular basis for engines, but there’s an “improved” DRCE3 and now a 4. What’s your combo and why aren’t more teams running the 3s and 4s?
CM] Same bore and stroke combos, and for my program I’ve got 4.700 to 4.750 bores. They raised the camshaft on the 3, and that’s what got everybody flustered.
HRM] Isn’t raising the cam better due to shorter pushrods and increased cam bearings for more stability at high rpm?
CM] That’s what it seems like it would be, but in this game, it looks better on paper. In reality, it isn’t always true. When you build it and then run it, a lot of times it’s a different story.
HRM] So the 3 architecture is not conducive to power?
CM] They flipped the head patterns, too, so they traded some places with the lifters. You used to use an offset rocker and offset lifter to clear the port wall, and as time went on there was no more offset for the rocker arms. They traded places with the exhaust side so a straight lifter is used. It looks beautiful, but we just can’t make it run.
HRM] So you stopped developing your 3 program?
CM] We haven’t started a 3 program, and I’ve owned my 3 for three years. [Aaron] Stanfield and others use a 2 block with a 3 head with some success. I’ve always liked the 3 head. On carburetors, the 2 had the advantage because Elite, other teams, and myself were outrunning KB. Most of us that had 2 programs were doing better than the KB 3s until this year. They were always 0.0100th to 0.0200th back, or sometimes just even, but they overcame on FI. Is it because it’s the 3 platform? Don’t know.
HRM] So you’re sticking with the 2?
CM] No, I have two 4 blocks now. In 2015 before the FI switch, that was going to be my top priority. My 4 was going to be a clone of my 2 stuff. I was going to use a 2 top end on top of the 4 block; with the cam being higher on a 3 than a 2, but lower on a 4 than a 3, that allows us to use 2 heads. There’s an extra bolt on top of the lifter valley that doesn’t allow you to use 2 heads on a 3, so you would need all-new heads. But the 4 block was made to use a 2, 3, or 4 head.
HRM] You run 4s in competition?
CM] I was, and got the block about 70-percent machined and we progressed from our carbureted 2s. We’ve been doing so much FI development that it got pushed to the side of the shop. My goal for 2017 is to do a 3 head on our 2 block, and if Pro Stock continues on its current path, then we’d like to do a 3 head on a 4 block.
HRM] Did you start with a carburetor baseline fuel map when first developing your FI program?
CM] Yes. Typically, we have a set of dyno carbs and a set of race carbs, and the same with manifolds. You have one to race and one to dyno. So with that at the shop, if we were 2,000 miles away, we could still beat on stuff at the shop on Mondays through Wednesdays before a race, looking for things without having anything out of our trailer. We started with a manifold we dyno’d that had a little more torque, but didn’t run as well on the shorter stuff needing a higher rpm. Talk about a crude part—my first intake was crude. I heard that KB tested 30 intakes before the 2016 season started. I’ve built or modified 10 to 15 intakes, and within those, I’ve done other things like move the injector to different spots. If I did a new manifold for every mod I’ve made, I’d be up to 35 at this point. Since coming home from the 2016 Finals[December 2, 2016], we’re on our third new intake. We’ve changed the shape of the plenum, the size, length of runners, how much taper it has—everything we did for carbs, except now you add an injector location and everybody is hog-tied. Well, you’re only as hog-tied as much as your imagination.
We did some math, calculated, and found some nozzles we could use to make a controlled fuel leak inside of our manifold that was worth 3 to 5 hp” — Chris McGaha
HRM] So where is the optimal location for a Pro Stock FI injector?
CM] I can tell you it needs to be as close to the plenum as it can, but not be in the plenum, or it won’t even do a dyno pull.
HRM] How about the combined lack of inlet charge cooling you’ve lost that carburetors provided, and the air inlet being so close to the hot track?
CM] Where you lose from carbs to FI is the cooling effect. That’s where the biggest difference is between the two. You’re trying to rebalance that to make the engine feel like it has the carbs on it now with FI, and trying to do what Mother Nature used to do for you.
HRM] Is there a way to cool the intake or charge?
CM] For 2017, there was a rule amendment stating all fuel must pass through the Holley injectors. See, we knew we lost the cooling effect and I’ve messed with stocker stuff, and what you do to keep the intake cool, guys use bags of ice on the intake and stuff like that. You’ve lost the fuel spraying in the cylinders cooling the air. I told my guys the fix is to have a spray bar inside of your intake manifold, then come out from that with a fuel line going to your regulator. The problem is that it’s so big it can’t idle with the spray bar spraying, so you need a way to activate it. You use those regulators made for guys who use Prochargers and turbos. If you shoot manifold pressure into them, it raises fuel pressure. You put a check valve in and use an outside source like CO2—which we all have in our cars—or something else, and you shoot to that regulator when you go to WOT. It shoots pressure, opening the check valve, and the spray bar turns on.
HRM] So are you or other teams doing this?
CM] I don’t know if that’s what guys are doing, but that’s one way it can be done. Did I do it personally? No, because I thought it was too gray of an area. Did I pay the price for not running it? I think I did, that’s why I ended up in Seventh Place. Who in front of me has it? I don’t really know. I know of some that didn’t have it, but nobody in front of me is admitting having it. Look, I’m sure there’s somebody in front of me that had it.
HRM] Could you spray ambient nitrous into the engine compartment, like some teams from the 1980s have been accused of?
CM] It’s been talked about for years, and I’m sure it’s been done. I know there are teams that have too much to lose, but I also think there are some that wouldn’t bat an eye about doing it. This comes from the street and the drag-radial world—over there, we call it “water meth.” You spray window-washer fluid and it cools the intake down to make more power. That’s where it’s from. You have to be creative in Pro Stock. If you don’t cheat, you have to learn to think like some people that cheat so you can at least call them out on it.
HRM] If it’s not in the rulebook, then it’s legal?
CM] An injector to me is a solenoid, so the way you make the spray bar work is with a solenoid hooked to your CO2, and that shoots air to your regulator and that raises your fuel pressure, so it’s too gray an area. We were so desperate at the end of the year that between Vegas and Pomona we were ready to rig the system up, but we didn’t use a solenoid at all.
HRM] So how was it going to work?
CM] We did some math, calculated, and found some nozzles we could use to make a controlled fuel leak inside of our manifold that was worth 3 to 5 hp. So the idea exists, and I wasn’t talking about it, but when we showed up at Pomona, everyone knew about it. I had Comp Eliminator guys come over to me to tell me about it. I wondered who kicked over the bucket! Then on Sunday morning, we’re handed the 2017 rule amendment and it’s in dark, bold, blue letters saying, “All fuel must pass through the approved injectors.” Well, that solved that problem.
HRM] Do you ever remove the ends of the injectors?
CM] We have—we’ve built tips, tried different tips, then no tips, and other company’s injectors that are supposedly better. If you get the hole too small and can’t get enough fuel through it, then it won’t run. I’ve gotten the same power with both the ones we use and other aftermarket ones supposedly better. If you ask one aftermarket guy about the injector we use, he’ll say it’s junk, but if you ask another, then he’ll say the other is junk. So which one is it, guys?
HRM] Why do you think the Mopars are consistently behind the GM Pro Stock cars?
CM] The Hemi has issues, and I know that because I ran it in 2012. I’ve worked on the Hemi and run the Hemi. Those engines at 9,000 rpm are 30 hp back on their best day from a Chevrolet. I’ve done everything under the moon, and I know what’s wrong with it. We dusted off our flow bench that we never use anymore, and I showed my guys what’s wrong with the architecture of the Hemi: they can’t make the torque a Chevrolet does—in fact, they don’t even get close. When they lowered the rpm in Pro Stock, it was instant death to Dodge. I even talked to Elite about this when they were thinking of going over to Dodge. I said, “Have fun going straight to the bottom.” They thought with this new head that is not a mirror design it would fix the problem, but the problem is the intake-port location. If you take the same intake port and just go down the head with it, that’s not going to fix it. It’s where the intake valve is positioned in the cylinder head. Even though the port is short, you used to make it up on the manifold because Dodge intakes were always 3/8- to 1/2-inch longer than Chevrolet. When I was doing the engine for Kramer last year, I tried to make it as much like a Chevrolet as possible. To judge on the dyno, you have specific dyno carbs that you never mess with—you never change jets, you never do anything to them, you just make sure they don’t leak fuel. But you measure how much fuel is going through them, and that’s how you can tell if you’re improving anything—by measuring fuel flow. I was able to get the Dodge to make the same fuel flow as the Chevrolet, but the Chevy on my dyno will make 1,500 peak hp. Now the Dodge could make about 1,470 hp, but that was at 9,000 rpm. It was a night-and-day difference. You had the same fuel flow, but the Dodge could not make the power at those fuel points. Others may want to differ, but I have tested them and have the facts to back up what I’m saying.
HRM] Where’s the most room for improvement in Pro Stock engines today?
CM] Right now, the most room for development is in the intake manifolds, and there’s some room left with [valve]springs. We’re just trying to get back to how it was with carburetors [in 2015] because we felt we had a good package. Maybe the whole motor needs to change because it’s on FI now. No one can say for sure that this is what it is. Like with an LS1, you put a carb on it and it will make more power than with fuel injection, but that motor was designed to be fuel injected.
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