December 2013 MAJOR Overhaul!!!2013 saw a complete engine overhaul. It was the end result of a couple years of chasing unknown issues... (and ignoring it in the garage!) It slowly developed a progressively getting louder knocking noise. I replaced the crank bearings with coated bearings to see if that might help, thinking the coating might add JUST enough thickness to compensate for any adverse wear. The bearings coming out didn't look too bad, and the new ones going in didn't solve the problem. :-( So maybe the problem was in the heads (sounded more upper engine anyway). So I went after the lifters thinking maybe one of them had failed. No dice there either. Lifters coming out looked fine, and still had the noise afterwards. :-( So it's not the top of the engine and not the bottom end... Has to be something in the middle. I finally decided to open it up early 2013 and that was when we discovered it WAS the middle - one of the wrist pin had walked out of the rod and deeply gouged the cylinder wall. Scrap that block... Yeah... Surprisingly the compression numbers were not too far off. But definitely found the source of the problem! One of the piston pins walked out of the rod (pins were press-fit into stock rods with the Ross pistons floating) and gouged the cylinder wall! At least THAT question was answered.... So moving on to what to do next...? Well, that answer was meticulously designed and custom produced. We built up this engine like no other - even MORE unique that it already was! I had given myself a few options...
1) Drop a stock NA engine and leave it alone. Call it a day... {yawn, boring}
2) Replace the necessities and do a twin turbo conversion... {yawn, been done before}
3) Replace the necessities and do a "stealth" remote mount single turbo... {very tempting, though has been done}
4) Take the road not travelled and push a few boundaries... NOW we're talking more my speed! Of the various options I had given myself, I ultimately opted for going after the unknown - let's build a 6G74 conversion! Wait, that's been done before, old news, both TT and NA. So what gives? {insert mad scientist laugh!} I wanted to carry forward the high-compression NA concept that had been successful on the 3.0 engine and build up a high compression naturally aspirated 3.5-liter 6G74 motor! And build it up we did! We bored the block from the stock 93mm out to 95mm, and factoring in the super-decked heads I have (42cc bowls vs stock 52cc), we designed a custom piston that would yield a 13:1 compression build - the goal was to have a car that could run on 93 pump gas AND run e85 for the extra power, depending on which tune was loaded in the AEM that was going to be used for engine management. Yes, we could have gone more for, but the car IS a street car, full interior, huge custom stereo, both show AND race winner. It's NOT a gutted shell race car. Were it such, I would have pushed the limits further (and someone should haha!). So I wanted a car that I could run 93 in and still travel without trying to plan-n-pray a trip around e85 availability (like I have been doing since the 2009 modifications), yet also run e85 for the added power it allows you to tune for. What we ultimately ended up with is a monster far beyond any other FWD Non-Turbo 3000GT/Stealth we've ever heard of! Here is the added/changed mods from previous builds (complete mods list below):
* 3.5-liter 6G74 block bored to 95mm yielding a 3.65-liter engine
* Custom flat-top Ross pistons at a 13.0:1 compression ratio LINK
* 3SX Custom 6G74 Rods LINK
* Clevite Coated Crank Bearings for 6G74 LINK - ( Coated 6G72 Bearings LINK )
* AEM EMS Series 1 + 3.5 Map Sensor + IAT LINK
-- Separate tunes for straight 93 pump gas and E85
* 3SX Custom DIY Poly Motor Mounts LINK - ( regular Poly Mounts LINK )
* KillerGlass Upper Radiator Hose LINK
* 3SX Custom NA Long Tube Headers by Kooks LINK
* 3SX Custom NA Race Pipe by Kooks LINK
* 3SX Custom Quad-Tip Cat-back Exhaust by Kooks LINK
* 3SX Custom Clear Timing Belt Covers LINK
* 3SX Solid Timing Belt Tensioner LINK
* Stock Twin Turbo Plenum SO what's the end result?
E85 Tune: 280.3 hp / 267.8 tq
Straight 93 Pump Gas: 270.0 hp / 254.5 tq The following graph shows the car comparing the E85 tune to the 93 tune. The E85 netted a gain of about 10hp and 13tq comparing peak numbers, but looking at the graphs, you can see it's across nearly the entire RPM range! | 
