Larger throttle body and injectors in my 94 SL? Help me learn please :)

Ok so I have a somewhat stock SL with 177k miles. Other than the typical smoke when it idles for a few minutes it runs great! I'm starting to do some upgrades and while building is no problem for me the problem is the physics behind it. I ordered a Jesters Chrome ECU from Adam (for the SL) and want to start tuning as soon as possible. I searched a lot and not found much on NAs but tons on turbos so I'm hoping to get more info here and hopefully this will help other wondering the same thing. I know my TB and injectors need cleaning but I was considering buying slightly larger ones instead. I can scale the injectors in the ECU and I assume that will keep it from flooding. Also I know on a stock NA larger injectors will do no good but with a larger TB and exhaust would I see any performance increase at all? My thoughts are if I'm replacing them anyways why not go slightly larger so when I start doing the work on my heads I'll already have good injectors and better TB. Any thoughts, theories and opinions are welcome.

Keep in mind I'm still learning this stuff. Opinions and tips and even long winded lessons are very welcome and encouraged but flaming and or derogatory remarks are frowned upon. Although I was a mechanic for years I never claim to know a lot or want to brag about how awesome my car is (although, even mostly stock, it is awesome to me) lol.

Thanks!

Stock NA injectors are plenty for a NA. A larger TB and exhaust really aren't going to do much at all for a NA 3s.

The largest gain you will get for a NA will be a flashed ecu, and/or more displacement. All else will do very little for the money sans giggle juice.

Thanks for your reply. So I should just buy replacement 210cc injectors?

I've already ordered downpipes and a better cat and while they may not do much I know they help some. I don't want or need a 500HP (just pulled a number out of the air) car so I'm not looking for huge power gains by replacing parts but I do want just a bit more performance as well as efficiency. When you say a larger TB and exhaust aren't going to do much, will the larger TB do anything for me or should I just have mine rebuilt or cleaned? I know I can only suck as much air in as my cylinders will pull but is the TB going to be any bottleneck at all, even if just a little? Consider that I will be having the heads done and getting better cams as well.

I love to tinker and learn so please forgive me if I ask for details.

Coopkill, I have the ECU on the way. More displacement will have to wait till I get a replacement motor :). Also keep in mind I will be rebuilding an engine in the future so anything I get now will go on the rebuild.

I know if I want a lot more power a TT is the way to go, but I love my SL. It was the first car I bought my wife after we got married and now she's got another car so the SL is now mine. We've had it for 14 years and it's been the best car ever! I know it will not be worth the money we put into it but as with all my hobbies I'll probably dump a lot into it anyways lol.

Rebuild/clean the TB, no gains to be had there. K&N filter is worth the price. A test pipe, or high flow cat is good. The long tube headers have some potential gains. Any other exhaust parts are going to be sound upgrades.

Lighter wheels, and interior are the other options.

Cool! I would gain a smoother idle from a rebuilt/cleaned TB :beguiled:. I tried to keep mine clean but even cleaning periodically it will still have buildup in the ports and places I can't scrub. I have a K&N in the stock housing but plan on getting a cone filter even if only for the coolness factor lol. I thought about headers but the cheep ones on eBay scare me and the 3SX ones are more than I want to pay right now (maybe on the new motor). I've heard good things about the larger downpipes and since the install is way easier than the headers I went that route with the free flow cat. Opening up the exhaust to 2.5" should help a little.

I've seen the stock 210cc injectors on eBay for $100 for a set of 6. Should I avoid those like the plague or would it be worth the money to put them for in for now and send mine of for a good professional cleaning?

Next tax return I'm swapping out the fenders hood and bumpers. While the bumpers are plastic anyways the fenders and hood will reduce weight. I'll probably concentrate on suspension more than the engine then if there isn't much I can do right now.

Just for learning sake, does anyone know the math, or know a site that has it, behind the engine size, injector size, intake size, exhaust size that shows what would work and why? While people doing this longer may know it won't work and I can take them at their word, I like to know why it won't work and/or what will. I'm curious by nature, sorry.

Thanks!

There is great info on stealth316.com.
There is a N/A upgrade bible on the other site as well.
http://www.3sgto.org/non-turbo-engin...hp-wheels.html
Look up any of GTWizzard's threads on both sites.

I'll check those out, thanks. I saw the dyno specs for the 3sx exhaust, that's why I ordered the down pipes and cat from them :)


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I know my injectors are probably pretty nasty since all I've ever done is run Sea Foam through the tank a couple of times a year. 177k on them can probably cause issues and I was going to throw some clean ones in there. Can anyone tell me if these are ok to use or should I avoid the rebuilt ones? I was going to send mine in to have them cleaned by one of the recommended services but still need the car running.

Thanks

You can get stock vr4 injectors for cheap/ almost free. And evo 560s super cheap. With a vr4 resistor pack you would be set for inj.
The nice thing about the flash ecu is you can get as big an inj as you want. As long as you understand that low impedence means you need resistors and high impedance means no resistors. You should be good. Match resistance of the new inj to the stock one for easier tuning better running.

Thanks Adam, that's what I was thinking but with others saying there is no point to upgrading the injectors I was just considering replacing with stock. I was going to email you but I figure I'd bothered you enough for now :biggrin2: and would post here to see if it was even worth it plus get some other info as well. The problem with stock is I'd have no reference for the latency table for the ECU. I know it is supposed to have the stock values in the ECU already but the file you uploaded had 227 for injector size and these are supposed to be 210. I'm not sure if the latency on these will make any difference at all or +/- 2% or larger or if I'd even notice but I'd rather be able to put documented values in there for the best tune possible.

I'm still waiting on the order from 3SX and now I'm wondering if there were other parts they had to get in first besides the ECU. Maybe they'll be shipped this week (fingers crossed).

I would get at least vr4 inj. Easy upgrade. Those numbers in the file are straight from Mitsubishi. So you have the stock settings for stock inj. What is wrong with your inj? Why not just clean em?

I've been searching and the best info I've gotten is send them off to get them cleaned by a pro. It's a DD so I cannot send them in and have nothing, that's why I was just going to order some and have these cleaned. I didn't want to tune my car with clogged up or dirty injectors then eventually get them cleaned or replaced and have to retune it with proper running injectors. They have been sitting for 2 years not running so I know they have to be a bit gummed up. Also the filter has not been changed much, maybe one or two times. In fact, I'll be scrubbing my plenum and TB clean as well. As far as cleaning them myself, I've only seen a couple of things talking about injector cleaning kits that you attach to the fuel rail and unplug the fuel pump fuse then run your engine on that stuff. I've read that using some of that stuff can break crap loose and cause the injector to stick open some. Back in the day I used to use that on other peoples cars but when the boss says to use it you really don't worry about what it could do, you just get paid for doing it lol. Then again I'd put O'reilly oil in cars for oil changes and wouldn't get that stuff near my car. I did however put an O'reilly clutch in my car. Biggest mistake of my life... except that one girl... but I digress. Now that it's my car I get paranoid about using those harsh chemicals in the fuel system. Without pulling the injectors out to clean, is there anything you personally recommend that does a good job? I do put Sea Foam in the tank periodically as well as in the oil (factory lifters still sound great most of the time when using that stuff).

Also, those numbers straight from the factory don't match what I read everywhere lol. I'm not trying to say anyone is wrong but the factory numbers in the ECU say 227cc and the injectors say 210cc. Odd.

Turbo intake manifold helps too I heard! I'm not a NA guy but have read that many times.

Interesting. I've read the same about the aftermarket plenums. I wonder if it's how the air flows through them. It's hard to wrap my head around the concept that a TB will not help but the parts between the TB and block will lol. I wonder if you would need larger valves or bigger bore for either of those to even matter.

The NA upgrade bible is nice but doesn't give much details of why/how it works, like the plenum.
Stealth316 has tons of good info but is kind of hard to navigate. Good thing there is a search feature that's better than forum searches lol.

Thanks for all the posts guys, I'm soaking all this in and doing lots more research!


Adam, just to go back to what I said earlier about numbers not matching, I saw someone referenced 220cc stock injectors. Now I've seen 3 different sizes referenced lol. I'm just going to try to get some cheap TT injectors and have them cleaned by a pro and call it a win :biggrin-new:

Stock NA are 210. I have seen people misstate 220 many times.

Stock NA are 210. I have seen people misstate 220 many times.

First of all decide if you want to keep the 3L
Best bang for buck by far is the 3.5L replacement.

Intake manifold I would use the Mitsubishi 9th gen Galant manifold, with the rear half flipped and welded back on.
Myself, I am also running an RPW 70mm bored TB, DR 272 cams, Extractors, 3" catback, Chromed ECU, AEM MAF style Meth Injection, with the lower/upper mani ported out, and the stock 240cc (remember, 3.5L) injectors re-co'd.
TT mani is good, this manifold has a proven 10HP on the dyno.

http://i9.photobucket.com/albums/a52...9/IMG_4661.jpg
i.e. $500 on extractors for the 3L? or $600+ for custom extractors for a 3.5L?
$1500 will get you a 3.5L and you will LOVE the torque increase.

I'm planning on rebuilding in the future so the 3.5 is definitely on the table.

That is a nice setup you have. I do miss my '01 Galant, although my wife never did like that car since we got screwed on the financing. We were a lot stupider back then and in desperate need for a car.

This is what I had, color and all. It was a fun car but I needed something larger at the time as I was starting a business and it would have been destroyed. So I bought a Montero Sport in '03 (loved the 3.5L) and actually just sold it with 214K miles on it and it was still kicking strong. We used that money to go back into0 the 3S :)
http://www.automobile-catalog.com/im...-galant-26.jpg http://www.automobile-catalog.com/im...alant-2812.jpg

why sugarcoat it. if you want more performance buy a vr4...

no point in wasting money for performance on a n/a to gain what 20-30 hp?

benefit of the n/a is as a daily driver with automatic and better fueleconomy.

Because I don't want a vr4. If the MAF goes out I can afford another. If the radiator goes out it's easy to fix. If a turbo goes out you are looking at a lot more money than I want to drop for that kind of repair.

Also, I respect your opinion and you may like your turbos but I posted in the NA section specifically to get advice on NA not advice on buying a different car. I may consider turbos much later but for now I am happy without.


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How have you progressed so far?

Did you ever do an injector upgrade to your N/A?