There are a handful of products on the market that can boost the Civic Si's mediocre K20A3 output (dyno'd anywhere from 130-150 whp, depending on who you talk to), namely forced induction kits from GReddy and Jackson Racing. We figured it wouldn't take long for Rev Hard to throw in its chips as well.
If you've seen this car around, it's likely because its owner, Cesar Loya, often hits the show scene, holding it down for his boys at Rev Hard. Loya brought his Celica to RH months ago for a custom turbo kit. He ended up driving the Si around so much that he bought it off Rev Hard top dog Myles Bautista.
The kit that Myles and his crew developed for the EP3 is not earth shattering and isn't meant to be. But what it does, it does well. It's a plug-n-play package that ships with Hondata engine management, meant to give an EP3 with stock internals a severe kick for under 20 grand (including the well-negotiated price of a new Si). Myles tells us that one of the next projects in line for this car involves a K24 swap with turbo, currently in development. So if you own an Si and just can't get excited about it, you have a few new things to think about.
Honda Tuning: So Myles, we'd like to believe you bought this car for a noble cause: develop a solution to give EP3 owners more power.
Myles Bautista: When we first bought the car--it sounds crazy--but we were so happy that it was so slow. We knew putting a turbo kit on it would be a big improvement. The first thing we did after we rolled it off the lot was put a body kit on it, then got into prototyping the kit. We tried the [GReddy] E-Manage on there. It's OK, but like the same thing on the RSX, it seems to have a mind of its own. One day it'll run well, one day it won't. It's not as picky as the RSX is, but you can still tell there's something happening to the ECU, that it's trying to correct somewhere. It's self-adjusting somewhere when it's reading something funny.
We worked with the E-Manage, then tried a couple of so-called "black box" manipulator companies that will remain nameless. When we put those on, they worked, but not to our specs. They manipulate the MAP pressure sensor, just so you can put bigger injectors on there. But on the factory MAP sensor, if they're just going to manipulate it, it's not gonna read positive pressure or boost. How would you be able to compensate for fueling if it's not going to read positive pressure? You're still working on the factory mapping of the vacuum from 0.5 volts or whatever. If there's no boost table on it, how's it gonna help? So we ran into that problem and that's when we called Doug and Derek at Hondata.
We sent the car to Doug for two to three weeks. For the first flash program that we came up with over there, Doug still didn't have any boost tables [matched] to the actual ECU fuel mapping. But he still got it to work better than the map manipulation boxes.
We also had to deal with the returnless fuel system. Basically you have to go to the brain. Instead of going in with a boost dependent regulator and clogging the return line to increase fuel pressure, you just go to the ECU. Add a couple of boost tables, set a couple of parameters in there to make the injectors fire longer [with more volume].
HT: In the end, you guys made 268 whp and 236 lb-ft at 9 psi, correct?
MB: That's right. And I think at 6 psi, we were at around 250 whp and around 220 lb-ft. Never got it to the dragstrip, though. We were having some problems with the clutch and we're waiting on a prototype from Competition Clutches.
HT: What did you learn working with the Hondata guys?
MB: On the dyno, Doug is never satisfied. He's always saying, "Let's try lifting this intake pipe" or "Let's make this pipe longer." He's always trying to extract more. I don't have that kind of patience to get 2 more horsepower!
HT: So the kit ships with a Hondata system?
HT: What was the process for prototyping your kit for that engine?
MB: We start with the basic tubular manifold that we make, then [do] the piping. The piping was a lot easier than the RSX. The Si is a little more square [up front], so the piping was easier to prototype. The manifold is typical of all Rev Hard designs. It's based off our tubular [design] and even though it's a cast piece, it's not a high-production, lock-style cast piece.
It's still a Rev Hard design, a proper, air-flowing piece where everything is directional. Coming out of the port, it ends up where the turbine inlet is, rather than casting a manifold lock-style, sticking a branch to it and letting the air coming out of the motor find its way to the turbo. [Our design] directs gas to the turbo instead of letting it find its way.
HT: That A3 head design is universally unloved by most tuners. I assume you're of the same opinion.
MB: Yeah, well, I think that's the reason our RSX-S kit makes 10-13 more [horsepower]. Same kit, same boost, everything.
HT: You're using the stock cam on this motor, right?
MB: Yeah, everything is stock. We haven't done any studies using different cams [on this kit] yet.
HT: You mentioned something on the tech sheet about upgrading the fuel pump, but you didn't say what you're using.
MB: Right now it's still stock, but we're thinking about using a Supra pump. The factory pump is good to about 400HP, but anything over and we'll need to upgrade the pump or put a return line on. There's only so much pump and injectors we can use.
HT: How much does the kit cost?
MB: Retail with the Hondata S100 is $3,800. That's everything you need, even if you're gonna build the motor. With the 550cc injectors and a computer that you can reprogram, you're good up to the turbo's capabilities, which is about 450 hp.
HT: Not bad, considering you can get into a new EP3 for about $16K. For another $4K, you're still under...
MB: Still under a Type-S, and you'll bust on a Type-S, no problem.
HT: Nice. What else has Rev Hard been working on?
MB: We've been playing around with S2000 turbo kits. Using an HKS F Con, stock motor and thicker head gasket, we got 365 to the wheels. That was at 16 psi, though. Using a 3mm head gasket lowers compression to around 9:1. We also tested at lower boost. At 6 psi on pump gas, we got 275 to the wheels. Torque was around 230 lb-ft-- it jumped almost 100 lb-ft. And it came alive at 4000-6500 rpm. Now if we could just crack the ECU...
HT: Yeah, good luck with that! So are we gonna see you racing this season?
MB: [Long pause]. The [NHRA] Hot Rod scene is ridiculous. Guys are running $30K, $40K transmissions. It kinda wipes that out [for us].
HT: You mean the Xtrac transmission, right?
MB: Yeah, and there are a couple of others. Any tranny that costs more than $5K, they can have it.
HT: How about using a K with a GM trans?
MB: That might be the only way I'll get back into the Hot Rod Class and build a K-series engine. It's simple; it's an adaptor. The K series turns the right way. If they could make it work with the B series. I have like eight or nine built B-series engines sitting around.That's the only reason I got out of racing, the transmission problems we had with the Honda. You just can't be competitive.
HT: Sell those B series and use the money to build a couple of K motors!
MB: Yeah, really. I used some of my B series with a couple of local guys I sponsored at the end of the 2004 season in Sport FWD [class]. And they ended up winning their events. We lent them our engines and they won! They're pretty happy. Now I just need to get the motors back
HT: Or get them to open the checkbook...
Cesar Loya's 2003 Civic Si
K20A3 with stock internals and cylinder head; RevHard custom intake w/HKS Powerflow filter; stock intake manifold; RevHard cast exhaust manifold; HKS Superdrag exhaust.
TURBO: RevHard Nutec 4045 ball-bearing turbo, Tial wastegate, Vortec blow-off valve, 550cc injectors (brand unknown), HKS EVC controller, 2.5-inch downpipe, Spearco intercooler.
TRANS: stock NRH3 with Competition Clutch clutch and flywheel; Driveshaftshop.com axles; Hondata K-Pro ECU
Rims & Rubber
Arceo 18x7 wheels; Pirelli P7 215-40
Ground Control; Stiph Fabrications chassis stiffening
AEM Big Brake kit; custom brake lines from Glen at Pro Flow Fittings
Outside:Buddy Club body kit
Alpine CVA-1003 DVD head unit; Polk Audio Carbon C400 and C500 amps; Polk/MOMO Series components, front and rear; (2) Polk Audio 10-inch subwoofers