Building a C43 Engine - Normal Asperation

[speedybenz]

Building a C43 Engine - Normal Asperation

I build a lot of AMA Supersport engines over the course of a year and have been looking at my C43 engine and trying not to pul it out of the car. But I keep hearing a voice voice in my head telling me to build it, build it.

So here are some of my thoughts on this:

1. Would like to increase rpm limit to 7500rpm. Even at that engine speed the stress will be less than a M3 engine which spins to 8000rpm with a longer stroke. So this is very doable with better rods and pistons. Need a chip tuner who can increase the rpm limit to 7500rpm.

2. Need good hand built headers, $1000

3. Need to examine the valve train weights and cam profiles to ensure that the valves can follow the cam at the increased engine speeds. Should not be an issue, ie; Webcam, Comp cams, etc.

4. I am almost positve the intake and exhuast ports are too large to function properly, so weld up exhaust ports and JB weld intake ports. Perform a very good 3-angle valve job.

5. Reduce intake & exhaust valve weight. Current Japanese engines are using 5mm valve stems with valve heade diameters as large or larger than whats in the C43, so have new valve guides machined to use lighter valves.

6. JE and Wiesco both make some good pistons, so find one with the proper diameter and weight.

7. Carrilllo will make a set of custom connecting rods to any length and bearing size. Carillo rods do not break.

8. Have the crank inspected and have the rod journals offset ground to use Honda sized bearing in the new Carillo rods. This results in lower bearing speed and thus less friction, more Hp.

9. Auto tranny and Torque convertor inspected to handle increase rpm and hp.

10. Rear diff. need to go to a 3.46:1 gear ratio to take advantage of the increased rpm


So with all the above you could possibliy have a well built engine that could be very reliable and spin to 7500rpm.

If you can achieve a 1.2 foot-pounds of torque per cubic inch of motor, which is around what a S2000 makes, then you could end up with about 320 ft-lbs of Tq and approx. 450Hp.

Very fun project.

Any thoughts and comments?

Jeff

[Denlasoul]

Wow! Thats some serious stuff you want to do. Ever since I got my C43, I have been wanting to improve its performance and handling. I have been thinking about going the forced induction route, but something about the n/a that keeps me lingering around.

This would be a great project. I dont have much expertise to help out, but let me know if there are things I can assist you with. I would really like to go this route too.

[714guy]

Wow sound like a very ambitious project that I think you can accomplish, with all you experience and all. I would love to do that to my car so i can fly by my friend's Honda but i have no clue what i am doin. Go for it.

Good luck

[Rocky]

speedybenz = benzpimp!

Go for it mang!

[WeatherMan]

This is a great project! I look forward to seeing your progress...

[BenzoAMGpower]

Since I import Motors from Japan anyways Ive been looking for a crashed E55, S55, CL55, or ML55. I was thinking of keeping it simple and just looking for a 5.4L M113 to drop into my 43.... but the search continues until a better alternative is found. Still, I would very much like to see what a built 4.3L motor could do!!! Go for it Jeff!!!

I think the only issue we really have to worry about is how we could reinforce the tranny to be stronger since you hear about C43 tranny blowouts everywhere!!!

[nukblazi]

Jeff,


What are the points to the exhaust and intake posts being too large?


hehe, Jeff... do it, tear her up, pull the motor, build it, DO IT

You are the man. Can I call on you when I am ready to convert my car to N/A?

[C280 JR]

If you build it, It will come-ch ch ch ch ch ah ah ah ah ah

Elvir

[nudymeyer6]

that is a good movie, c280 jr.

[speedybenz]

The tougest part of the whole deal is to find someone who can bump the rev limit up. Powerchip said they could but when I sent the ECU in they then told me they could not. But first they tried to tell me all the reasons why you should not raise the rev limit.

Then I told them to go ahead with the chip mod and it made almost no difference on my C43. Nothing, no top end power, no engine response improvement. So I had them remove the chip mod a week later. Powerchip told me they were not about Hp numbers, just how the motor felt. Whatever?

But even without a rev limit increase I am still interested in doing the project I still think you can get close to 350Hp to the wheels.

The choke dimensions on the ports are not small enough by 1st glance and that causes the air velocity to be slow and really hurts the cylinder filling as the valve closes on the intake. With higher air velocity the mixture continues to jam itself into the cylinder after bottom dead center, when the piston is going back up the cylinder to top dead center.

[nukblazi]

Jeff,


I had seen a thread I think you started about a piggy back system. Have you contacted them? Renntech can raise the redline, do you know if they outsource? Have you contacted upsolute?

Because of $$ i hate to say it but have you thought about a Motec engine management system. They have base system packages at good prices.

I've never heard of someone welding in smaller ports. Is that safe? Do any of the other 430 motors use a different head you could bolt on?

Manley Performance makes (and imports) really kick A hardened titanium valve train components, you might want to see if they can do anything for you.

[BenzoAMGpower]

Originally posted by speedybenz
The tougest part of the whole deal is to find someone who can bump the rev limit up. Powerchip said they could but when I sent the ECU in they then told me they could not. But first they tried to tell me all the reasons why you should not raise the rev limit.

Then I told them to go ahead with the chip mod and it made almost no difference on my C43. Nothing, no top end power, no engine response improvement. So I had them remove the chip mod a week later. Powerchip told me they were not about Hp numbers, just how the motor felt. Whatever?

But even without a rev limit increase I am still interested in doing the project I still think you can get close to 350Hp to the wheels.

The choke dimensions on the ports are not small enough by 1st glance and that causes the air velocity to be slow and really hurts the cylinder filling as the valve closes on the intake. With higher air velocity the mixture continues to jam itself into the cylinder after bottom dead center, when the piston is going back up the cylinder to top dead center.

so the powerchip ECU upgrade for the C43 has no gains?

[speedybenz]

The PC did not increase Hp on my car, but yours could be different.

I have been talking to Upsolute a little and they are looking to see if they can raise the redline.

It is pretty common to weld inside the ports to change the shape and volume. The exhaust port is the port that normally gets the weld. A lot of tuners use JB Weld on the intake port because they stay cooler. I know it sounds a little backwards to put JB Weld in an intake port but it is commonly done.

[nukblazi]

Glad to say I learn something everyday. That's awesome. Where would find the parts to weld in? Custom? How do you go about determining the flow?

[speedybenz]

It takes a lot of experience to know what will give the best air flow through a cylinder head and a lot of it is an art.

It is pretty easy to make the ports larger and the Flow Bench will show higher air flow numbers and it would first appear that the engine should make more Hp since the head flows better.

But in real life the tuner has just increased the port cross section area and this will slow the air flow and 99 times out of 100 will result in lower performance and a slugish motor.

Then you have to remember that an engine is a select set of parts that were put together to perform in a certain way, based on the static and dymanic compression, cam timing, lift and duration, exhaust pipe configuration, cylinder head design, ie; a 2 valve, 4 valve or 3 valve or even the 5 valve designs.

I could go on and on, but if you want a pretty good and very up to date site to read up on engine design and such try: http://mototuneusa.com/thanx.htm

However, the rules change for Supercharged and Turbo engines. These types of engines do want a pretty big port because your shoving air into the cylinder at 4-20psi. So you want a good flowing port of good size and cams that have short durations and lots of lift. You just want to stuff as much air into the engine as fast as possible and then close the valves to keep it in there.

[nukblazi]

Awesome reply, thanks Jeff.

[Luwin1026]

I bow down to this speedybenz guy - even though I'm mechanically retarded, it all sounds oh too cool. Sure beats dropping your car off with a blank check to have them build you a motor.