Blew my K20a engine on AA3 - Advice needed

**NKC** · May 15, 2018, 04:21 PM

A little update:
Went with a k20z3 with less than 6000 miles at a dirt cheap price of $850usd. Our ecu's are locked so we're putting in another ecu and he'll dyno tune it with the supercharger from scratch.

From the look of things, the heads were running dry for more than 3 minutes and everything is fried on my "old" k20a engine. Cavitation resulted and there was no oil in the oil pump. Kinda rare I guess but the oil pump failed and my plans of rebuilding this"exotic" k20a Red top is out of the question and it'll be a kickass coffee table.

My fears of blowing up another engine is gone now since the k20z3 is abundant and cheap and it takes less than a day for re&re.

Can't wait to rip it on track on the weekend to see how it runs.

**Mitchell** · May 16, 2018, 10:03 AM

Originally Posted by NKC

A little update:
Went with a k20z3 with less than 6000 miles at a dirt cheap price of $850usd. Our ecu's are locked so we're putting in another ecu and he'll dyno tune it with the supercharger from scratch.

From the look of things, the heads were running dry for more than 3 minutes and everything is fried on my "old" k20a engine. Cavitation resulted and there was no oil in the oil pump. Kinda rare I guess but the oil pump failed and my plans of rebuilding this"exotic" k20a Red top is out of the question and it'll be a kickass coffee table.

My fears of blowing up another engine is gone now since the k20z3 is abundant and cheap and it takes less than a day for re&re.

Can't wait to rip it on track on the weekend to see how it runs.

Just curious, what was the rough cost on the tuning?

**cvjoint** · May 16, 2018, 07:27 PM

Originally Posted by NKC

A little update:
Went with a k20z3 with less than 6000 miles at a dirt cheap price of $850usd. Our ecu's are locked so we're putting in another ecu and he'll dyno tune it with the supercharger from scratch.

From the look of things, the heads were running dry for more than 3 minutes and everything is fried on my "old" k20a engine. Cavitation resulted and there was no oil in the oil pump. Kinda rare I guess but the oil pump failed and my plans of rebuilding this"exotic" k20a Red top is out of the question and it'll be a kickass coffee table.

My fears of blowing up another engine is gone now since the k20z3 is abundant and cheap and it takes less than a day for re&re.

Can't wait to rip it on track on the weekend to see how it runs.

Smart. The K20Z3 is high output and reliable. Wear it out and throw in another one.

I've never thought about a worn oil pump. That will surely pull with it the whole block. Many of us don't really rebuild engines after a certain race hours count has been reached. That's the right way = expensive way to do it.

These wet sump pumps, as well designed as they are for a Honda 3000 lb hatch with no aero, are really getting pushed to work on an Atom. I'm pulling consistent sustained 1.4 G which what most production dry sump cars can do.

**NKC** · May 18, 2018, 11:06 AM

Another update:

Atom was dropped off on a friday night and new K20z3 was put in by Monday morning. Since the ecu is locked, we had to quickly source another ecu and get a flashpro for the dyno tune. Unfortunately, the guy couldn't retrieve the stock map to have a baseline comparison so it had to start from scratch.

Base run on a Mustang dyno:
Max Power: 213.6 @7500RPM
Max Tq: 154.4 @6750RPM
Pump gas

After Tuning:
Max Power: 223.2 @7500RPM
Max Tq: 162.7@6250RPM

The numbers look weak for a K20 supercharged but we're on a Mustang dyno and what matters to me is the difference before and after tuning. Too bad I can't get a pull on the same dyno with a completely stock K20a superchaged. In addition, it's a very conservative tune for reliability going forward with this season.

The tuner said the adjusted number on a non mustang dyno would be something like 262hp and 186tq to the wheels.

Looking forward to testing the new engine this weekend.

**NKC** · May 18, 2018, 11:06 AM

Originally Posted by Mitchell

Just curious, what was the rough cost on the tuning?

4 hours at $160cad/hour = Total $640cad

**McFred** · May 18, 2018, 01:35 PM

Originally Posted by NKC

After Tuning:
Max Power: 223.2 @7500RPM
Max Tq: 162.7@6250RPM

K20 supercharged

Which supercharger and what pressure? What's your red-line?

**cvjoint** · May 18, 2018, 04:16 PM

The numbers seem pretty low. Maybe the pulley size wasn't calculated correctly for the new engine and you're boosting too few psi?

How does one correct from 223 to 262? That's quite a jump.

**NKC** · May 19, 2018, 10:02 PM

Still on the stock JR supercharger and tuner said it was running at 5.8 psi.

The numbers are adjusted to a dynojet figures.

Got a hold of an identical aa3 supercharged from the same year to pull a dyno run on at the same place on the same conditions. His original motor (k20a) pulled 14hp and 12tq more than my tuned k20z3.

**cvjoint** · May 21, 2018, 11:56 AM

Originally Posted by NKC

Still on the stock JR supercharger and tuner said it was running at 5.8 psi.

The numbers are adjusted to a dynojet figures.

Got a hold of an identical aa3 supercharged from the same year to pull a dyno run on at the same place on the same conditions. His original motor (k20a) pulled 14hp and 12tq more than my tuned k20z3.

Makes sense then, 5.8psi is fairly low. If you pulley up to near 10 psi then you'll see ~280whp.

**jeff8407** · May 21, 2018, 03:17 PM

What did your tuner says about your Air Intake Temperatures (AIT)? 5.8 lbs of boost is a very conservative boost rating on the Jackson unless your not intercooled. Most Jackson set-ups aim for 7-8 psi of boost--more boost typically increases the AIT too much due the inefficiency of the roots type blower and you have to take timing out or use race gas.