Chris Kraft Build Thread_Big Turbo car!

[chris_kraft3]

Do you think I can make a serious Ecomodded vehicle out of this? (Rhetorical)



I am super excited to show off what I am working on. I have been into cars for as long as I can remember. Sustainability has been something I have admired for a long time also. I drive quite a lot each and every year. For sure I have been driving a solid 20k miles a year per car since 2004. I have always been excited in being able to go fast, but with a small motor. 100+hp per litre is my style.

Now this car i am in process of converting was built for speed. Now it is time for both, for me to be able to go faster and better and cheaper at doing it.

I will have to post up the pictures of what I have done so far. My testing grounds are running between Wichita and OKC on I35. I use the same two gas stations when I travel this trip. My wife goes to school in OKC but I have a mowing business in Wichita. During the spring and fall I driving back and forth weekly. We have a FA5 Civic Si you see in the back of the first picture that can average up to 34-35mpg on this trip. Most of the time it gets 32-33. I had my Mr2 retuned last November for more power from the people that built the motor. I am at 249whp and 181wtq in my 4agz(t)e 1.6l that came in this style of car.

When the car was first tuned I wasn't getting much better than 17-19mpg. That is very low for this car/engine. But first time I launched the car it did a 4.4second 0-60mph. Not a whole lot of complaining you can do with those numbers except the cost. I have a much larger width of tread touching the ground than what the car came with to be able to put down the power. Since I am getting away from so much acceleration I am less concerned with this.

So let's start off with where I have made changes. There are multiple holes in the front bumper that serve no purpose at this time. The turn signals are inset behind the bumper a few inches. There are two holes in the bumper right below the turn signals that serve no purpose. So a theory I had was to fill those holes before I did a run to OKC. Now I'm not one of those guys that does the ABA testing because I am so excited of my gains that I don't want to drop back. I bought two small pieces of plexi and blue painters taped them over the holes in the bumper. I filled my tires with a bit more air 28psi front 34psi rear. I also did the cruising style without A/C (shirt off). I also turned my mirrors inward. Before these mods I was catching around 23.5mpg hwy. Before was with harder acceleration though. Now I had forgotten to account for tires size difference. If my new tires are 100% then my factory would be 94.4% so I take this into consideration now. I have read much on this website to come up with these ideas in the front bumper. With these changes I have accomplished 29.8mpg hwy. I am hella excited about this number.

But I have much to accomplish from this. My mod I have done this week was to kick my tires up to max pressure. 44psi front and 50psi rear. This has made my rolling resistance less, so much that you can feel the difference. I also did a K&N filter cleaner to my filter. Wow it was dirty. The motor can now run on a lower rpm while being able to pull the car. With such large cams in the car it hasn't ever really liked the lower rpm's.

I am planning on picking up a set of factory sized 14in wheels in place of my 17in this weekend. I will do the pizza pan face on them and going from a front tire of 205 and rear 225 down to a factory width of 185. But the issue with this that may be contradictory is that height will be close to factory specs bringing my rpm up a bit while cruising on the hwy. I will have to test the differences on this with an ABA test.

I would like to hear your feedback on my project. Thanks for reading.

[hondaguy72]

Without reversing many of the performance modifications (camshafts especially) it will be difficult to achieve great mpg's. High load, low rpm power is how you get great economy out of a car. That being said, you could realistically get 30's or better if tuned. I had a cammed, turbo d16 in a 1998 civic that could still get 40mpg on the highway.

[chris_kraft3]

I'm sure great in my eyes and great in other's eyes will be two different things. I would completely satisfied with close to 30mpg city. But what I am really eye balling is for 38mpg hwy. And still be able to run with a Viper when the guy pulls next to me and is wondering what the hell this ricer car is doing.


Thanks for your feedback.

[cleanspeed1]

There's a lot left on the table with the combination you have, and the vast majority of it is going to be in getting the fuel and timing curves optimized. Like hondaguy72, I immediately looked at the cam timing as a standout with the existing cams that you have. The thought is getting a set of adjustable cam sprockets and doing loops on the intake and exhaust cams and seeing how much of a difference it would make in terms of boosting the torque lower in the powerband. Elsewise, I would get the stock cams and reinstall them. You are not going to miss the power, and if anything the car will run stronger because you brought back some of the missing low end torque.

I am passing on what this guy did with his DSM Laser.

http://www.gassavers.org/garage/view/207

[Backtobasics]

As others have said, tuning of the PCM will probably offer the biggest improvement.
I presume the post turbo exhaust has been tweaked for low back pressure?
What does the underside look like? Belly pan?

[chris_kraft3]

I have HKS adjustable cam gear sprockets that are both set a 0degrees. I guess when I said built I didn't mean I was going to take away my power to gain fuel economy, that would be retarded for this car. A person doesn't spend big money to make power and then start retracting solid custom parts to gain small percentages in FE.

I have no belly pan at all as we speak. Planning on a full pan front to engine bay area and maybe between the motor area and the rear bumper but I need to leave under the motor open as the motor makes a lot of heat.

The exhaust is a full 3in with no bends but rather cuts welded back together, you can believe there is no back pressure. The back pressure only comes from the turbo.

The standalone Autronics computer was tuned to run around 15.1 afr at 3000 rpm area. It is fairly clean running at that range.

I could retune with cam adjustment for even more torque but I am not willing at this time to do that due to cost effectiveness. And as I said this car makes 181 peak lb ft torque at the wheels. I could only bring that down a few hundred rpm by cam adjustment.

[Bill in Houston]

What are your cruising rpms? Maybe a larger diameter tire would help lower the rpms and get you to a more efficient operating point? Since you have a jillion hp and torques, you can go pretty big without acceleration being an issue.

[cleanspeed1]

Nothing that has been suggested will take away power, just change the powercurve. Where are the hp and torque peaks at? How much boost are you running to get those numbers?

[Phantom]

If you have problems with running at a low idle RPM have some one tune the idle. This can be done by adjusting the idle portion of the spark table if the rpm bounces around a lot add a few degrees of timing, if it idles fine you can reduce the commanded idle rpm a little bit and possibly reduce the timing a little. I would try to keep the idle timing with in 8degrees of the surrounding cells, if there is a hesitation when giving the car gas off of idle try bringing the timing closer to the timing values the cells you enter when leaving idle.

The stability of the idle can also be adjusted with the Idle air bypass tables.

[chris_kraft3]

Originally Posted by Bill in Houston

What are your cruising rpms?

Since the highway that I usually run on is I35 and the speed limit is 70mph I cruise at 72 to keep out of boost and stay in a vacuum state. Any slower than that when climbing any sort of incline it goes straight to a boost state. 72 is perfect with the oversized tires I run. 5.6% Taller actually. But to save patch touching the ground i will be trying out a set of 185's instead of my 225 rears and 205 fronts. I will lose most of my height difference from stock but it may put me in a better rpm that makes power more easily.