How to tune a car right: Part 1, tuning GM with Top Speed Cincy

·11-min read

Not long ago, I wrote a story about a pony car tuned with a supercharger. The blower install had been done properly. Then the car's owner bolted on a set of great looking wheels wrapped in good looking but inexpensive rubber. On my first test drive, I couldn't get any of that supercharged sweetness to the ground. It was the perfect ride for parking in a Burger King parking lot on a Friday night. I tooled around on a Sunday drive, shaking my head that someone had spent five figures to get more power the right way, with a clean install, then wiped out the gains so thoroughly that the stock engine would likely have overwhelmed the tires.

This got me thinking about the ways people ruin their quest for horsepower, either on the front end by not insisting on a clean install and paying the money for it, or on the back end with supplemental purchases like cheap tires or cheap gas. So I called three tuners, one focused on GM, one on Mopar, one on Ford, to find out what people should know about how to get the best power for their goals, and how to make sure they are able to use all that power. The first interview in this three-part series is with Blake Leonard at Top Speed Cincy in Cincinnati, Ohio. He's been in the business for 12 years and specializes in modern domestic performance, mostly GM-based. The interview has been edited for clarity and concision.

Where should someone start with tuning their GM product?

The most important thing with any build is to have an end goal and a budget, and let the person you're dealing with tell you if that budget is realistic. With an end goal, you're not buying parts twice. If you say "I want to make 700 wheel [horsepower]," how do you want to do it? We’ll go over nitrous, Procharger, turbos, and what type of fuel so we can pick out an injector size that won't max out when you get there.

Most buyers aren’t looking down the road?

A lot of the time, they're just kind of building the car as they go, which is fine. But if you have some forethought, you can put together a combination that's going to be wonderful for the final product.

Let’s say you just wanted a camshaft and you say, "I might go boost down the road, but it's a little out of my budget right now. I still want a good choppy idle, what do you recommend?" We could put a camshaft in that car, but if I didn't know you might go boost down the road, we could put one in there that's based around being all-motor [naturally aspirated – ed.] and it's not going to be ideal for boost. You're going to leave a lot on the table when you go boost. Or I can put a camshaft in your car that will still give you a good idle, you still get power gains, but it will also be boost friendly down the road, and you only sacrifice a little bit right now on all-motor.

So getting the right parts for your ultimate build is the best way to save time and money in the long run.

Absolutely. Combination is everything. If there's one thing I want people to take away, it's that the tuner doesn't make the power, the combination makes the power, the tuner makes the combination safe. People get hung up on these dyno numbers, and they think the tuner can just put it on "Kill" and make all the power in the world. But the tuner doesn't really make the power. Yes, they can affect how the car runs, they can make a little bit more peak power than another tuner, but two very good calibrations should make almost identical power on the same car.

What do you mean by “The combination makes the power?”

The combination is which parts you use to get what you want out of the car – headers, cold air intake, stuff like that. Those are the parts that make the power. The tuning is the calibration inside the ECM that we manipulate to provide the fuel and ignition timing and drivability that’s needed for that combination. The car doesn't know what parts are on it, so when you put a cold air intake or exhaust on a car, the car still thinks it stock until it's been tuned. You're getting more air in and more air out, so you're going to make more power, but the motor is delivering the same amount of fuel, so you have a lean condition. The software tuning is what makes everything safe to go out and beat on and have fun. And the difference between a safe tune and a "hot tune" is only a couple of horsepower – it’s really not much.

What has YouTube done to the tuning world – people thinking, “I saw it online, so why can’t we just do this?”

That can be a huge pain in the ass. If someone comes in and says, "Hey, can you do it this way? I saw it on online." I'll say yes or no as to if it's going to work. If not, I'm not going to do it that way. If you want to find someone that will, that's fine. Everyone thinks that it's easy because you’ve got these handheld programmers, but they're not good. Every single one I've seen, it’s a stab in the dark. Every vehicle is different. You could have two identical cars off the assembly line and they might need to be tuned differently just because of mechanical tolerances and how things fit. They’ll be close but they may not be exact, and it’s not something you can typically get a mail order tune for. Custom calibration is always the way to go. The only time I would recommend a handheld programmer is if you just need to drive your vehicle to the dyno. Any major combination or anything with a decent amount of work done to it needs a custom tune.

You need a doctor who understands the patient's vitals.

Absolutely. I make jokes with some of my doctor friends about that. If somebody brings in a car to be diagnosed, I have to call him and give them the bad news like, "Hey man, cylinder three’s hurt." It’s wild, but it’s become a crazy, crazy industry.

So how do you find the best doctor?

If you have a tuner in mind that you want to use, talk to them for 15 or 20 minutes about your combination. See if there are parts you they want you to have before bringing it in. A big one that's overlooked is spark plugs – as soon as you start making decent power, you need to go to a colder heat range spark plug. I’d have guys show up, we’d strap the car down on the dyno, I'd make a half a hit [the beginning of a dyno run – ed.] and get detonation or knock, and I’d pull a spark plug and find out it’s still the stock plug even though this guy has a Procharger and camshaft. You can really waste money by not having all your ducks in a row beforehand. And even worse you can hurt an engine.

What if someone already has a tune they’re asking you to fix or get more power from?

Say your car has heads and cam and you wanted a new intake and throttle body put on. I could get in there and see the way they tuned the vehicle, and it may work for that combination, but it may not be how I prefer to do it. So typically, on something like that, we'll just start over. I don't want to be chasing different bugs around if it’s something that I'm not familiar with. If you take your car to a new tuner and they don't want to use the tune that's already on there, and they want to start over, don't be surprised.

Then back to where we started: What’s the best way to start with a GM product?

I think the magic combination, especially for GM-based stuff from ‘97 and up, has been intake and exhaust. You get some sound, you get more power. Anything past a cold-air intake you need to get tuned for safety. After that, the magic part is a camshaft. They give you peak efficiency of that engine, given what you're trying to do.

With an intake and exhaust, what's a good number to expect in terms of gain?

Usually 10 to 15 wheel horsepower is realistic from a cold-air intake, cat-back exhaust, and tuning.

What’s a reasonable gain to expect from cam and headers?

On early-model LS’s we were seeing 30 wheel horsepower from headers. The more late-model stuff, we only see about 15 to 20, because the companies have started to make more efficient exhaust systems. The camshaft, probably another 30 to 50 horsepower. It’s when you put them together that they really shine – you don't want to do a camshaft without headers because you’re sacrificing a lot of power, like having a one-inch garden hose and necking it down to a quarter-inch. Anywhere from 60 to 100 horsepower is not out of the out of the question as far as gains with an intake, cam, headers and exhaust.

A lot of guys with huge numbers run E85. What’s the performance gain there?

On an all-motor combination, the most I've seen from E85 is about 20 horsepower to the tire just from a fueling change. Say a turbo’d LS comes in, it's making 700 horsepower to the tire on 93. If it has the adequate fuel system and we put it on E85, it usually picks up to 60 to 80 wheel just from fuel – same boost, same everything else. It's huge.

Do a lot of folks want too much power for the money they have to spend?

Yeah. I try and explain to people it's really expensive to go cheap. If you see a set of headers on eBay for $200, but all these other quality headers are $800 to $1000, you’re going to get what you pay for. It's a disposable income industry. If you can't afford to do it, then save up or don't do it.

Where do people tend to want to go cheap?

Fuel injectors. And you need to ask your tuner before you purchase. There's something called injector data, multiple different tables in your tune calibration. If those numbers aren't available or are incorrect, your car will not run properly. A good set of injectors for an LS engine to make 700 or 800 wheel are usually around $1,000, and you will get injector data you need to properly calibrate. You can find the same injector size on eBay – I've seen them as low as $200 – but they don’t come with injector data, and they’ll never run properly.

Anywhere else people skimp?

I stress the importance of running 93 octane fuel.

People buy cheap gas after a tune?

It's unbelievable. I’ve had people bring me a brand new Corvette, drop $20,000 on it, it’s detonating on the dyno, and come to find out they have whatever the cheapest octane is. That is such a common thing. It is so important to run 93 in these for not only power, but longevity, too. You're missing out on probably 20 to 30 wheel horsepower from running cheap gas. And it's not healthy on the motor, either.

What parts away from the engine do people ignore to the detriment of the tune?

Suspension. More modern cars are subframe vehicles with a lot of rubber bushings for a smooth ride. As you start making more power, you can potentially get wheel hop – all those rubber bushings are flexing and twisting instead of staying stiff and putting the power to the ground. Wheel hop is a very harsh condition for the vehicle because you're getting that on-and-off power in a split second, and it can break parts. Everyone wants power before doing suspension or other components that will help handle the power.

This is another subject to speak to the tuner about?

Absolutely. If it's a quality tuner and they care about the customer, they're willing to talk to you. Call the shop that you're going to be using and say, "I'm looking to do this kind of power, do I need to upgrade suspension? What do you recommend?" These guys are driving essentially two or three different modded cars a day. We get to feel what each part feels like. If someone asked me, "I want to lower my vehicle, do I need coilovers or should I do lowering springs?," I can say, "I drove this car with coilovers, it didn't ride very well, but it handles well, so if you're not worried about ride quality, go coilovers; if it's a daily and you want ride quality, you want lowering springs." We have experience with these parts and usually we can tell you what works and what companies stand behind their product.

If you ever want a recommendation on a clutch, call a shop because they've driven multiple cars with aftermarket clutches, typically a couple a day.

No one likes the guy that calls for all the free information and never comes through. But if you're willing to use them for tuning, they should be willing to talk to you about what they recommend and what they want you to use.

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