Head Games, Big Ball Bearing Boost & Laughing Gas
In the last 4G63 Power Options series article, we started looking beyond the bolt-ons. For this installment Doug's Dynopower wasted no time in focusing on the cylinder head which had escaped unscathed so far. A ported unit, complete with stainless-steel valves and stout internals, is an excellent way to maximize the efficiency of the turbo's boost.
Once Doug's Dynopower removed the stock head, the crew was amazed with the virtually perfect stock ports; no severe mismatches between the valve seats and pockets as most production heads have.
At any rate, another head was ported and fitted with heavy-duty stainless valves from Supertech Performance, Inc. The Supertech valves are black nitrided for increased durability and less friction. The valve's seat surface is hardened as well-a much-welcomed attribute with today's fuels.
From a performance standpoint, the valve's undercut stems let more air pass the valve even at low-lift or low engine speeds, which means more potential down low in the powerband. A fresh set of Crower valve springs and retainers round out the valvetrain combination.
Upon installation, Doug's Dynopower used a metal head gasket and ARP head studs. Sometimes engine builders get carried away with hogging out large ports and fitting oversized valves in a cylinder head. The result is a race head that may produce big numbers on the flow bench, but won't perform on the street in the real world. The head, turbo and cam are a team and need to deliver the goods at a usable engine speed. A turbo engine's head doesn't necessarily need the same mods as a N/A cylinder head.
For a street-use 4G63 engine, new stock-size valves, a set of fresh springs, mild port work and a set of cams like the 414 Crowers produce a head package capable of supporting upwards of 500 hp. (A side note, the Venom sheetmetal intake helps tremendously from 4000 rpm on up.)
While the use of an aftermarket intake on a 4G63 is always in dispute; on this application the Venom unit is very effective. A loss of low-end torque is miniscule when compared with the mid- and top-end gains made with the straight-runner intake. This reiterates the importance of supporting mods and we should add the intake manifold to the aforementioned list of turbo, head and cam.
Topping the 4G63 with a built head netted roughly 20 whp when ran at the same boost level. Boost built faster and much more smoothly. The engine revved to 7500-8000 rpm very quickly in any gear.
Distinctly different was how the engine seemed to make the same power as before with 1-2 psi less boost. The gains from the head and valves would be even more noticeable at higher boost levels. Driving the Galant on the street and dropping the hammer at mid-range in the powerband causes the car to spin all four tires at 18-19 psi-quite a sight to behold. With the Garrett T3/T4 ball-bearing turbo starting to spool at 2000 rpm, turbo lag is not a concern.
The T3/T4 turbo Doug's Dynopower had used on the Galant flows roughly 49 lbs of air. Doug's Dynopower says it worked great, probably the best sized unit for a street vehicle that can also handle up to 25 psi for the track on race fuel. Wanting more flow for the engine, Doug's Dynopower elected to jump to a Garrett GT Series full ball bearing unit from Tial Sport. The Garrett GT3040 model flows 55 lbs of air.
To complement the new turbo, Doug's Dynopower also used a Tial 46mm external wastegate. The Tial unit is beautiful, perhaps the last external wastegate an enthusiast will ever need to purchase. It can handle up to 800 hp in flow.
The turbo system upgrade is completed with a Tial 50mm blow off valve. Doug's Dynopower reports the turbo comes on so smooth and strong and doesn't stop pulling until 7600 rpm, and even then, it's still making excellent power. Although peak torque numbers are decreasing as horsepower numbers increase, the engine's broad torque range is still substantial. Output only increased 10 horses at peak with the GT turbo at the same boost level, but this increase is over a 4000-rpm span. The old turbo had little lag; this unit has no lag.
Add in the increased durability of a true ball bearing design and the GT is a worthwhile investment. Having used the old turbo on a few other cars and made 440-450 hp at the wheels at 22-23 psi, Doug's Dynopower hopes the GT will make 480-500 hp at the same or slightly higher boost levels.
Tuning has been relatively straightforward, so far, although the injectors are pretty much beyond their capacity with duty cycles at 100 percent. Compensating with increased fuel pressure via an SX regulator has helped somewhat, so it's time to increase their size from 550cc to 620cc or larger.
An often overlooked key to making any 4G63 DSM run to its fullest potential is guarding against detonation or knock. Ask anyone that has dyno'd their car how much power timing is responsible for and their response will include numbers varying from 50-80 hp -substantial power to sacrifice.
Some engine designs like more timing than others. The Mitsubishi engine seems to be happy with a fair amount. The Technomotive Datalogger easily traces the timing and monitors knock under boost. The goal is to keep the timing above 15 degrees at WOT and the knock sum below a value of 5.
The Doug's Dynopower engine doesn't like to make consistent power on 91-octane, regardless of the ambient air temperature. Although 100-octane unleaded is for sale at the pump, Doug's Dynopower was looking for a booster that could be added at any time.
Nitrous Express developed just such a product. Designed to be used in N/A, turbo and all-nitrous applications, Nitrous Express' fuel booster has its largest power effect when used in conjunction with nitrous. Doug's Dynopower used it with 91-octane pump gas with profound effects. Timing increased to 20 plus degrees at WOT; knock sum was zero. The ECU didn't have to pull a crazy amount of timing out due to knock.
Some will argue to simply add more fuel to combat knock. Sure, more fuel will cool the combustion chamber, but it reduces power output at the same time. Maintaining an O2 reading of .85-.90 volts has produced the best results so far.
The intercooler used on the car is a Spearco air-to-air unit that flows over 1000 cfm in a top-to-bottom core arrangement. While it has done an admirable job thus far, Doug's Dynopower needs more area and it plans to upgrade to an APEXi Skyline side-to-side core arrangement.
In the meantime, Nitrous Express has developed a new intercooler sprayer system that uses either nitrous or CO2. It douses the intercooler core with an extremely cold charge of gas. What a difference-the Galant runs like it's 40-50 degrees cooler outside with the system on and spraying.
There is a side effect; boost increases slightly from the cooler and denser air. It also leans the engine out at higher engine speeds, but larger injectors will cure that. For anyone in a high-heat climate or with a seriously undersized intercooler this is a product worth looking at.
Doug's Dynopower determined the stock chassis needed some attention. Not wanting to lower the car's ride height, Doug's Dynopower employed KYB AGX struts all the way around and added a new set of stainless-steel brakes from Diamondstar Specialties.
The Galant, being longer and heavier than a first-gen Eclipse, still needed more stability. Mofugas Motorsports has engineered its Whiteline anti-roll bars especially for the more-brutish VR-4. The result is a truly profound difference in handling, though braking power still needs work.
Having exhausted almost all of the available bolt-ons for the 4G63, all that's left are a set of Fidenza cam sprockets to dial in the cams, a larger throttle body unit and AEM's EMS management system; when the 4G63 box comes out. In the near future, Doug's Dynopower has decided to build a new short block for the Galant, complete with forged pistons and rods and deleted balance shafts.
With the car's full weight and Doug's Dynopower's strip aspirations one has to ask about the driveline. This question will be answered in the next installment. Stay tuned.
|Hp||Tq||Gain Hp||Gain Tq|
|Power Realization Chart Round 1 Modifications|
|Power Realization Chart Round 2 Modifications|
|TeamRip Mass Air||271.5||302.7||11.6||-1.4|
|Power Realization Chart Round 3 Modifications|
|Turbo XS HPBC||319.8||348.7||12.6||14.1|
|Power Realization Chart Round 4 Modifications <16G turbo at 19 psi>|
|Power Realization Chart Round 5 Modifications|
|Garrett T3/T4 (15psi)||355.2||n/a||12.8||--|
|Garrett T3/T4 (18psi)||378.1||391.7||22.9||20.2|
|Power Realization Chart Round 6 Modifications < |
|Previous Power (No NOS)||397.3||412.8||--||--|
|Ported Head (19psi)||417.3||394.1||20.0||(-18.7)|
|Garrett GT3040 (19psi)||428.2||423.7||10.9||29.6|
|Nitrous Express I/C Spray||437.8||423.5||9.6||(-0.2)|