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Discussion Starter · #1 ·
So,
Thanks to you guys on here pointing me in the right direction, I've found LOTS of performance enhancements for the L05.
For those who have upgraded their L05's, what upgrades did you do, and how did each effect your gas mileage?
I see that Jegs says a throttle body spacer will net you a 10% increase in torque, 15% horsepower, and 8% mpg. are these number accurate, real world numbers, or are they best case scenario numbers? They mention their injector spacer adds 15% to air flow but doesn't mention anything else.
How much of an effect will the other modifications have. Will any other help fuel economy or will they all hurt? Which ones add actual power and which ones only improve throttle response?

For instance :
Headers
Dual snorkle air cleaner
Injector spacer
Cam
Heads
Intake manifold
Fuel pressure regulator
TBI
 

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Headers will get you about 25 HP.

The injector spacer will get you a lower power band, but the HP will be about the same.

You can not get a better intake manifold unless you go to a non EGR, and carb it or adapt a TBI to it.

Cam will get you some HP, but you will have to get a custom chip for it. The amount will be determined by the cam and custom chip you get for the computer.

Dual snorkle air cleaner just gets more air to the air box. 0-3 HP

Higher rate valve springs, and longer ratio rocker arms. HP???

Put a spacer under the injector tower to open up the air path. Some gain 5 HP?

Depending on what heads you get will determine the affect. You may need a specific intake manifold for the heads. 10-300 HP

Fuel pressure regulator is determined by the HP, and you also may need a higher output pump as well.

TBI...you can get up to 2 inch (54mm) TBIs. Stock is 42mm, but you need to upgrade the injectors and bore out the manifold to match. You may be limited to certain manifolds, which could limit the HP. 54 mm are good up to about 530 HP, but stock is good up to about 240 HP. available in 42, 46, 50, 54 (maybe 58) mm. Get the size that your HP requires. Too much can actually hurt you.

You can get up to 90#/hr. injectors for high HP applications. You need a lot higher pressure, and much greater flow for more HP. Upgraded pump.

You have to balance the above mods to get them to work together to get the most HP.

Gas mileage is determined more by your foot than the configuration of the engine. Low speed gas mileage will drop a little. High speed will be determined by the actual speed, and the aerodynamics. The car requires a specific amount of HP to go a certain speed. Gears can change the mileage some when you go to extremely high numerical ratios. Hot rodding between lights will lower gas mileage.
 

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Discussion Starter · #3 ·
Thanks Fred,
like it or not, it looks like you are turning into my mentor on this project, lol.
Ahh, so many decisions, I've got time since I'm not about to do ANYTHING to the car right now since I don't have a garage and the temperature is UP to 21 degrees right now.
I just want to make sure I do all my homework now so that I can make the best decisions when it warms up.
I'm not wanting to build a monster, but I do want more power than what I've got. I also want to lose as LITTLE gas mileage as possible. I know keeping my foot out of it will help. But I need to be careful with things that will still hurt fuel economy even when I'm babying it. So I guess when I say fuel economy, its what it would be capable of getting if I do my part.
Some say I should have waited and purchased an LT1 wagon, but it was a good deal AND most importantly, I needed a car, so it was either get an L05 wagon, or get NO wagon. Guess why I chose what I did, lol
What would make me ridiculously happy would be LT1 performance and fuel economy with pre 93 interior. I know you can get an L05 up to LT1 power levels, but I'm doubting you can do it for the same MPG.
 

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If I were to spend the kind of money you are about to, I would look for an LS series Iron block engine. A used 5.3 or 6.0 iron block will make a lot more power (without modification) for a lot fewer dollars than modifying an LO5. You will have fewer issues, and the car will get the same basic gas mileage as the stock LO5. There are instructions in the LS swap section. You need the engine, trans, computer, wiring harness, truck FEAD, motor mount adapters, Trans mount, headers, duals, radiator fans, fuel pump, fuel lines, and probably a few other things. You have to modify the wiring harness to work with your gauges, and electrical system. The harness can be purchased for about $200 if you can not figure it out.

A good u-pull-it engine and trans with the computer, wiring harness, and peripherals will cost you about $1000. The rest is about another $300. Your labor is not included. You can make room for a computer by moving things around the engine compartment. The easiest space to acquire is to move the vapor canister under the wheelhouse with a bracket from an LT1 car. You can offset some of the cost of the new engine and trans by selling your old one like you said above. If you are removing the engine for upgrading, you are half the way there anyway. The LS swap is about the cheapest bang for the buck you will find. Look for a low mileage LS series engine with its trans Try to stay away from the latest models, because they can get a little complicated with fly by wire throttle, and VVT in the engine. Mechanical stuff is relatively easy to fix/modify, electronic not so much.

My goal is to put a 6.0 (LQ4 or 9) truck engine in my 91. You can bolt on stuff up to 450 HP on an LQ4. The LQ4 uses regular gas, and the LQ9 is a higher compression engine, and requires premium gas.
 

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Discussion Starter · #5 ·
I TOTALLY agree that the LS swap is the best option. The only problem I have with it is that I don't have a garage or engine hoist. Whatever I do has to either be done with the engine in.... or I have to work on the car at my in-laws, which is an hour away, which is usually a good thing LOL. But working on it there would be awful, lots of people I don't want to see, and lots of people that have free reign to the garage and mess with EVERYTHING that's there. So, any engine swap would involve me buying a cherry picker and working at home in the gravel. Which is most of the reason I opted out of the LT1 swap idea.
So, maybe I just need to learn to live with what I've got.
 
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