Getting my ponies to run faster--I'm bored, Have you tweaked an Ljet? Options

[computers4kids]

I have a stock 1.8 with an Ljet that runs good but not the fastest gocart on the block. I've done a bit of reading on my Ljet and am looking for any tweaks to get some more horsepower--I know, I'm starting down that slippery slope. Here are some ideas that I've heard about...what do you think...

Raise the fuel pressor on the system to 60 psi---rams more fuel through stock injectors...suppose to even atomize it a bit better.

Install a variable pressure regulator with a higher pressure fuel pump that senses engine load off the manifold which then increases fuel pressor with more demand.

Play with the air/fuel mixture screw

Loosen the tension on the air sensor flap

Trick the CPU with resistors into thinking the engine is cold thus enriching the fule mixture

Put an aftermarket kit on the cold start valve as a way of pumping extra fuel into the system when throttle is moving towards full throttle position.

Put a wind-up propeller on the back that can be released when extra umph is needed

Any ideas????????

[rcrgrl]

you could add one of these.
http://www.techeblog.com/index.php/tech-ga...wered-vw-beetle

- sorry, you probably wanted actual helpful advice !!

[drewvw]

i dunno man....seems like tweaking the mixture to get more power is a baaaaad idea.


what about exhausts/dizzy/ignition upgrades...thought about that?

[computers4kids]

you could add one of these.
http://www.techeblog.com/index.php/tech-ga...wered-vw-beetle

- sorry, you probably wanted actual helpful advice !!

I like people who think outside the box...

[computers4kids]

i dunno man....seems like tweaking the mixture to get more power is a baaaaad idea.


what about exhausts/dizzy/ignition upgrades...thought about that?

Exhaust...did that
igniton...did that

[drewvw]

Time to build a larger motor then. Get to it! (IMG:style_emoticons/default/sawzall-smiley.gif)

[Andyrew]

25 shot of nitrous?

One of the little sneaky systems?

http://cgi.ebay.com/ebaymotors/Cool-Shot-N...1QQcmdZViewItem

[computers4kids]

25 shot of nitrous?

One of the little sneaky systems?

http://cgi.ebay.com/ebaymotors/Cool-Shot-N...1QQcmdZViewItem

Finally, a sensible solution...

[rcrgrl]

(IMG:style_emoticons/default/av-943.gif)

[rpmmaxxed]

25 shot of nitrous?

One of the little sneaky systems?

http://cgi.ebay.com/ebaymotors/Cool-Shot-N...1QQcmdZViewItem

That little guy for real?

[Andyrew]

worth about 10hp.

Theres a much better kit out there (thats a used kit.) but I cant find any online currently..

Andrew

[Dave_Darling]

Raise the fuel pressor on the system to 60 psi

In other words--make it run rich.

Install a variable pressure regulator with a higher pressure fuel pump that senses engine load off the manifold which then increases fuel pressor with more demand.

Make it run rich.

Play with the air/fuel mixture screw

Make it run rich.

loosen the tension on the air sensor flap

Make it run rich.

Trick the CPU with resistors into thinking the engine is cold thus enriching the fule mixture

Make it run rich.

Put an aftermarket kit on the cold start valve as a way of pumping extra fuel into the system when throttle is moving towards full throttle position.

Make it run rich.

Put a wind-up propeller on the back that can be released when extra umph is needed

Hey, an idea that won't make the engine run rich!!!

Looks like we need a little basic edumication on how internal combustion works, here....

You do want to burn fuel, yes. But fuel needs air to burn! There is a chemically "perfect" ratio of air to fuel when you are burning the fuel--it's the amount of air that contains just the right amount of oxygen to completely combine with the amount of fuel during a burn. This winds up being about 14.7 parts air to one part air (all measured by mass, BTW). This is called the "stoichiometric" ratio.

If you put more air in than can be "used" by all of the fuel, a number of things happen. One of the most important things for modern cars is that catalytic converters work much worse--but that's not a concern for us. Our concerns are that combustion temperatures tend to get higher with more air, and less overall energy can be used to move the piston downward in the cylinder. This means less power! Having more air than the "correct" amount is known as a "lean condition". It is easy to get this in a 1.8; just let it develop an air leak...

If you put more fuel in (or less air) than this "perfect" amount, you get a "rich" condition. This causes a number of things to happen. For one, catalytic converters work poorly and can actually be damaged by a rich-enough mixture! (Again, not something most of us have to worry about.) You also get cooler temperatures, because the extra fuel actually helps cool off the engine parts a little bit. And, up to a point, you get more power. That point is, depending on a lot of circumstances and exactly who you ask, around the 12.:1 or 13:1 ratio. And we're talking a very little more power, really--probably on the order of a couple of HP in a stock 1.8 motor. When you get much richer than that, the power drops off drastically.

Get rich enough or lean enough, and all sorts of bad things start happening. The mixture can wind up being very hard to light, and the flame front may actually get extinguished in some cases! This will show up as misfires, or just plain not running. Rich mixtures can foul plugs fairly easily and cause buildup on parts in the combustion chamber and the exhaust. Lean mixtures can actually lead to holes burned in pistons, and other heat-related disasters.

Anyway, the point of the above is that just dumping more fuel in is likely to be counterproductive--chances are you will make less power, and get much worse fuel economy and you might even cause other problems which will be $$$ to fix.

The key is to get more air to move through the engine, and then add the little bit more fuel that is needed to match that air. Within limits, your L-jet system is very capable of doing that. Try a real header (not a "collector and muffler" like a Bursch) like the Tangerine Racing Super Header. It's bloody expensive, but it is probably the best single bolt-on HP improvement you can do without trying to figure out a turbocharger setup.

--DD

[Andyrew]

Good for one shot.. if you upped the jet (more hp) its even less.. lol

If you really want some juice.. throw some real stuff in there.

Andrew.

A wet system would be perfect. I wouldnt go over a 50 shot. You'll have plenty of fun!

Andrew

[computers4kids]

The key is to get more air to move through the engine, and then add the little bit more fuel that is needed to match that air. Within limits, your L-jet system is very capable of doing that. Try a real header (not a "collector and muffler" like a Bursch) like the Tangerine Racing Super Header. It's bloody expensive, but it is probably the best single bolt-on HP improvement you can do without trying to figure out a turbocharger setup.

--DD

Dave, thanks for the advice--I know you are residing "king" when it comes to the L-Jet. I was hoping one of those ideas that I mentioned might be a winner since they were taken from Robert Bentley's book, Bosch Fuel Injection & Engine Management.

I have done some reading on the "Tangerine Racing Super Header." You are right..."bloody expensive" to the tune of $1200.

What parts of their system and options is absolutely necessary for a "street application?" Realistically, what kind of gains would I see? Is this an item I would ever see for sale on the board? Later, if my 1.8 dies and I decide to go to a 2.0 like the one on my garage floor, will I beable to use this exhaust system on it?

Sorry for all the questions...but this is a very expensive venture...but might be worth it.
Mark

[srb7f]

Why not simply go with a 2.0 now if you're going to spend that kind of money? I was able to get a good running one, clean and refurbish (even powdercoat engine tin and airbox) for about the price of the exhaust alone. That's about 20 hp, which would be tough to get out of a 1.8 without radical modifications. It's really a remove one engine, install and plug in the new one.

[computers4kids]

Why not simply go with a 2.0 now if you're going to spend that kind of money? I was able to get a good running one, clean and refurbish (even powdercoat engine tin and airbox) for about the price of the exhaust alone. That's about 20 hp, which would be tough to get out of a 1.8 without radical modifications. It's really a remove one engine, install and plug in the new one.

The 2.0 was from a parts car that had "fuel issues" according to the previous owner but hasn't run in many years. My guess is it probably needs a rebuild. I'm a little apprehensive about building it myself, CB performance (local bug shop) doesn't want to rebuild it. I can't see buying a good running 2.0 for say $1000 to just buy some time. My thoughts were since the 1.8 runs great, just a bit under powered, I might go with the expensive exhaust if it will migrate to the 2.0 when the time is right.

If I had 5K laying around, I would just buy one of Jake's motors.

[Joe Bob]

Like the scene from your avatar...which btw is MY OLD RIDE....more power is an excuse for more cubic inches....

[Cap'n Krusty]

Of your list, only the last option is worth considering ................ The rest are not gonna work like you think. The Cap'n

[Andyrew]

Tell me what color the intake runners are on the 2.0..


You can rebuild the 2.0... i'd say the weakest link is the cam... Just get a cam that will match what you have and your desired rpm range..

OR get a megasquirt system. (or both)

The megasquirt system will allow you to make the most out of what you currently have and what you will have when you make more mods...
300 bucks total is really worth it..

Correct air fuel ratio is everything...

GL