refresh951

In order to stay focused, a reminder of what I (and I believe several others) are trying to accomplish. We are using some new (and old) approaches in order to produce 3L+ motors at significantly lower costs. And I mean lower cost, essentially 1/3 the cost. Cost is a MAJOR factor in making decisions for this build. With cost reductions of this magnitude their will be risks. Part of what I am trying to do is evaluate these risks.

To my knowledge only two hybrid strokers (filled, Mitsu rods, SBC pistons) have been built and initial results look VERY optimistic. Much more work must be done. For Sid to design and build the first motor, drive it 12K miles, produce 500+ hp, make over 100 1/4 runs (with ground breaking results) on a motor the cost around $3200 is nothing short of amazing!

The design shows promise and this build is just another brick in initial development.

eman930

I totally agree! Keep building and keep sharing, you guys are the back bone of the community, I think your build will be awesome, With every build there are risks, Not everyone has a $100,000 build budget so keeping cost down and building sick motors is a great way to get more of us involved. Keep up the good work

TonyG

It's well documented that using an "extra" injector is a poor solution for adding additional fuel into an otherwise dry intake.

The reasons stated are exactly correct: fuel distribution

Which also happens to be the primary reason that TBI was replaced with port injection long ago.

Adding fuel this way on a high hp turbo application is just asking for trouble.

Google away


TonyG

Rogue_Ant

The primary reason that TBI was replaced with port injection is emissions and economy.

I asked for data multiple times from robstah that shows port + fractional TBI caused unbalanced fueling. Nothing has been shown.

We have already proved that it works, is very controllable, and has multiple benefits.
So you google away if you feel like it.

TonyG

Doing what you're doing makes sense and is not uncommon. I've seen this done with pistons and valves on 951 engines many times.

A piston is a piston... as long as the part fits correctly and is engineered to do what you intend it to do in terms of weight, strength, dimension, metallurgy, etc... there's no reason not to use it.

This type of thing is done all the time with Chevy and Ford engines.

And is the same reason I bought up using a GM LS1 PCM to control the car vs the "antique" Bosch DME. Cheap, works, and far more advanced.

But just to be clear... 1/4 mile runs in no way load an engine like road racing. Night and day.

TonyG

Rogue_Ant

TonyG

Exactly... which was caused because of poor fuel distribution, poor fuel atomization, fuel puddling, etc... (All fixed by using an individual injector to shoot the exact same quantity of fuel at the back of each the intake valve.)

These problems were what they had to address on engines making what... 1/2HP per cubic inch on production engines. These same problems have a FAR greater impact on engines making 2-3HP+ per cubic inch. Big difference.

All the same problems you'll have with a 5th injector

Unless you put in an EGT on each exhaust port on the dyno, you don't know that it's controllable. And you won't be aware of the unequal fuel distribution either. Which is exactly the problem.

What you're requesting of him is very common knowledge. I wouldn't waste my time with it either.

Anyway, I guess time will tell the story....

Good thing it's not on my dime.... :-)

TonyG

Rogue_Ant

I did not seek out robstah to request data. He volunteered his opinion, but then when asked for a bit of proof - couldn't produce any. Pretty much the same thing you just did.

TonyG

What size injectors does he need? I might have a set I can give him for free.

TonyG

Rogue_Ant

Tony. He is running the equivalent to 100# injectors. If find that we need to get 4 x 100# port injectors, then that is what will happen.

AL951

Not to get into the argument, but all modern F1 engines that produce more the 350Bhp per liter are not port injection or direct injected they are good old TBI. And I think no one here can argue with the R&D that is done by such names in the industry like Ferrari, Mercedes Benz, Renault.

Regards,
AL

TonyG

Are you smoking crack?

They are injected above the throttle plate. At the top of each stack. With one injector per cylinder.

TonyG

AL951

No Tony, I not smoking crack or anything. positioning of the injector before the throttle is call TBI.



in this pic it can be clearly seen.

Regards,
AL

TonyG

No. That's not what's known as throttle body injection.

Throttle Body Injection (TBI) is where you have a single injector or a group of injectors (more than one) injecting fuel into a common plenum feeding (typically) all of the cylinders.

TBI was a replacement for a carburetor. And was used to directly replace the carburetor on the same intake as a stop-gap measure because port injection was a new concept on OEM's.

F1 application of a single injector, per port, above the throttle plate is not "Thottle Body Injection". It's what's known as "Port Injection". The fact that it's behind the throttle plate, in this context, is irrelevant.

Again... TBI is where you have a single or multiple injectors feeding a common plenum.

Port Injection is where you have a single injector feeding a single cylinder.

TonyG

AtharRazvi

Out of curiosity, when you added the 5th injector at the TB, did you ever have an O2 sensor on each cylinder?