2G What do I need to run an 18G turbo? 97 GST

[Junzu]

Sent out my stock turbo for rebuild, he threw in a good condition 18g for 100 bucks! Comes with turbo lines and manifold. Ready to bolt up.

This would be my first time modifying. I have much to learn about boost and its requirements. Engine is STOCK. Only modifications to my 97 GST is an ACT 2100 clutch I threw in with the ACT streetlite flywheel.

My question is, do I need a Walboro 255 and better injectors to run this turbo? I'd like to know the appropriate CCs if better injectors are needed. What tuning software do I need to run this turbo? Stock SMIC ok, or do I need FMIC? Better radiator and/or thermostat needed? Do I need any engine internals or is stock okay?

Everything besides clutch and flywheel are bone stock. No exhaust, suspension, intake, or better piping. Would like to know what I need for this to work without breaking something. Thanks!

 

[99dsmer4g63]

This info can all be found by searching. Bit since you asked.
850cc injectors
255 fuel pump
Wideband
Something to manage fuel
Things I would also do:
Cold air intake
Rewired fuel pump
Full exhaust
AFPR
Fmic
Easily make 350hp with that setup on 93 pump.
If the motor is in good health and maintenance has been taken care of it will be fine.
-Daniel

 

[chrysler kid]

Dont mess with it for now. Put the stock turbo back on and start saving for the other parts first.

Basically even if you put in a bigger turbo the computer is locked in its stock configuration. So you would add a bigger turbo and the mass air flow sensor will see it sucking in all the extra air and basically shut off the fuel to prevent the motor from going to unsafe boost levels. Even adding injectors and fuel pump does not change how the ecu sees the air coming in, and the ecu still thinks its a stock eclipse. You will need to buy an ecu sold by ecm link to unlock your computer for programming and tuning. So you have to "tune" the car to accept new values for boost and fuel settings

Some cars are easy. You buy a new mustang gt and call a shop for a dyno tune. Yeah I got a cold air intake and i want the car tuned, sure the tuner says, that will be $800 and ill get you an appointment for 3 months from now

Dsm's have hardlocked computers, the 98-99 cars came with a black box ecu that will accept outside programming if you know a tuner who uses evo scan software. most shops dont offer much service like that for our cars anymore, most shops wont do tuning for these cars. Its not a growing platform and the software isnt widely used across different makes and models, they'd rather charge the mustang guy $800, than charge you $800 and find out you have a boost leak or ignition miss on the dyno and have to scramble around trying to fix random issues that always pop up on older cars

You'll need:
Dsm link ecu and software ($800)
Fuel pump and wiring kit ($300?)
Fuel injectors. Lets say $300
Fuel pressure regulator $120
Turbo install kit $100
Front mount intercooler kit $500

So youre now $2200 into a build to run a $100 turbo.

So lets go backwards, you wait a year and collect all these parts, you gonna want to run the $100 turbo and maybe make 300 hp? Or you want to spend $1100 on a super nice turbo thats gonna make the guy tuning your car sweat balancing fuel data tables on the dyno because that expensive turbo makes a lot more power

The turbo is just one piece of the build

If you really just want some extra fun try to trade that 18g turbo for a nice 14b turbo off of a first gen dsm and have more fun getting to know the process. The 14b will probably gain you about 15-20hp and really change your redline power band. The stock t25 really strugges to make power to redline on those cars and the 14b really makes the car feel like its a hard acceleration to redline

 

[Spleen8urLSX]

ECMlink is NOT a standalone, don’t go around telling new people that, while it’s a very capable solution it’s no standalone as far as capabilities go.

OP to correctly answer your question, technically you COULD run that 18g at wastegate pressure the way the car is, it would in no way be moving enough air to outflow what the maf and stock injectors and pump could do. The original ECU calibration has its limits but also leaves a pretty decent window compared to more modern stuff, the “golden rule” 17 years ago before things like ECMlink were available was 15lbs on a 16g as long as the pump was upgraded as the stock pump is the first weak link to run out of steam in the fuel system. Many of us did this with a stock ecu, with a stock maf and stock injectors, without any hiccups as it wasn’t moving more air than what the maf and ecu could compensate for and the cars ran like they were meant to if installed properly. The injectors were the limiting factor at that point and when you hit the limit of what they could do and needed to upgrade to get more out of it was when a management solution like ECMlink (or for several of us in that era a piggyback like an safc or maf translator) became necessary, as there’s no upgrading injectors without a way to control them and no forcing the stock 450cc injectors to go any further without a way to control them and take some fuel out (factory programming is very rich, back in the day you could afford to lean the mixture out to go a little further and pick up some as you weren’t demanding as much fuel from them, but kind of nonsensical to do this with 450s in the year 2022). The harder part is getting the 18g to maintain the 9-11psi it’ll make on wastegate pressure and not gradually creeping to an unsafe level under heavy throttle, can be done but a lot of hassle for minimal gain being that an 18g or 16g isn’t really moving any more air at that boost level than something like a 14b but with added lag over a 14b or t25.

With that being said it’s the year 2022 now, with what we have available now it doesn’t make a lot of sense to go through the trouble to make the 18g work properly with what you have until you have the proper support for it unless you really need to get the car back on the road. At the levels it would be safe at with what you have the performance benefit would be so minimal you wouldn’t really notice it IF there was any gain at all as that turbo doesn’t really shine until you get it 20ish psi or more.

Long winded I know, but I like to give the new crowd an actual explanation in a way that can make sense opposed to spewing nonsense or just saying no.

 

[habitatguy187]

I disagree. A 18g at 15psi will feel MUCH faster than a t-25 at 18psi. Put it on, run wastegate pressure until you re-wire and/or upgrade your fuel pump, then run 15psi or whatever the ecu will let you get away with until you get something to tune with.

He's still on stock exhaust so boost creep shouldn't be an issue either. You can do it now, which is just install. Or you can reinstall the T25 now and then later have to take it off again and put the 18g back on. Essentially doing the work twice. An 18g barely outflows a 16g, it will be fine.

 

[Spleen8urLSX]

I disagree. A 18g at 15psi will feel MUCH faster than a t-25 at 18psi. Put it on, run wastegate pressure until you re-wire and/or upgrade your fuel pump, then run 15psi or whatever the ecu will let you get away with until you get something to tune with.

He's still on stock exhaust so boost creep shouldn't be an issue either. You can do it now, which is just install. Or you can reinstall the T25 now and then later have to take it off again and put the 18g back on. Essentially doing the work twice. An 18g barely outflows a 16g, it will be fine.

Oh you’re absolutely right, but I’m talking bottom of the barrel boost, while that was the old “golden rule” I also once data logged that and it made my back door pucker a bit reading it, 15lbs on the 16g was safe but pushing it haha. However I’d be skeptical to push an 18g quite that far as like you said the difference is minimal but indeed there. You do bring up a valid point with the exhaust, I didn’t think of stock exhaust being on the table however you’re right, it probably wouldn’t creep.

 

[chrysler kid]

Oh you’re absolutely right, but I’m talking bottom of the barrel boost, while that was the old “golden rule” I also once data logged that and it made my back door pucker a bit reading it, 15lbs on the 16g was safe but pushing it haha. However I’d be skeptical to push an 18g quite that far as like you said the difference is minimal but indeed there. You do bring up a valid point with the exhaust, I didn’t think of stock exhaust being on the table however you’re right, it probably wouldn’t creep.

After having several second Gen's with a 16g turbo im telling you that they can maybe run 15psi without hitting fuel cut on a hot summers day. Cold night youre going to get a little boost creep on a long 3rd gear pull and get fuel cut

If you just bolt on an 18g you would have to run it at waste gate pressure 12psi basically. And then im not even talking about the fact its probably an ebay 18g

I will always recommend a 14b to start the modding process. Its a good upgrade

 

[Spleen8urLSX]

After having several second Gen's with a 16g turbo im telling you that they can maybe run 15psi without hitting fuel cut on a hot summers day. Cold night youre going to get a little boost creep on a long 3rd gear pull and get fuel cut

If you just bolt on an 18g you would have to run it at waste gate pressure 12psi basically. And then im not even talking about the fact its probably an ebay 18g

I will always recommend a 14b to start the modding process. Its a good upgrade

And I told you up there “15psi was the golden rule”, so you’re simply reaffirming what was already stated that a bunch of us have done time and time again. As far as creeping up on a cold night, anything I’ve ever tried to run that low of boost on I ported the wastegate passage and never had that problem. As far as it being an 18g I’m running on the assumption it’s an old “Greddy” style 18g or and older 18g from sbr or something along those lines as I’ve never seen a China 18g ready to bolt on on to a dsm, If the guys talking some Subaru bolt on we need to back all the way up here but I’m assuming since he asked it’s configured for a dsm. With that being said the old cast wheel 18g’s BARELY outflow a 16g, if at all at that low of boost levels, definitely not significantly enough to where the stock ecu and fuel system can’t handle 10-12lbs from it. Even the billet wheel 18g jusMX offers now is only a step up and flows in comparison to a 68hta v1, which people have ran on wastegate pressure along with the td05 20g on the stock ecu and fuel system, again no improvement to be desired but has been done and done safely numerous times.

As far as the 14b goes you’re not wrong, however I’m not going to go recommending everyone new go get a 100k+ mile 30 some year old 14b or pay for a refreshed one when they may be willing to pay for something like a 16g or 20g that’s still super easy to use and in that class. Ironically I’ve been doing this 17 years and have had a few 16g’s, Holsets, Borg Warner, etc, and the 14b Justin built me that’s going on my car now for “number chasing” is my first 14b.

 

[CrackedDSM]

14b's also don't live nearly as long above 18lbs as a 16G does(stock for stock. Not talking about upgraded thrust bearings/collars/whatever other magic is done to help the 14B live longer).

Also curious to know what 18G it is. I'd keep whatever you have on the car now, and just build up some parts. Throw on a 16G(if your 18G sucks), some 550's and a Wally 255HP + AFPR, intake/exhaust, and a good ECMLink (or H8/Flashable ECU and tune) and it'll be a very nice street car, that'll get you used to maintaining a modified turbocharged 20+ year old sports car, and how these cars respond to mods. Then when you're an expert and run 11's on the 16G(After replacing and adding things more than just my basic list I gave), you can start upgrading and going bigger from there.


But even with 2022 and all the "tech" we have, you'll never convince me there's a better turbo for a purely street DSM than a 16G. They're just so robust, last so long, so easy to tune with, and their torque hit is ADDICTIVE. That MHI 'you've got....BOOST MOTHAFU**A!!" is so fun. Linear power is fun, sure, but something about the instant hit of a 16G always feels...right. Not to mention even on a heavy 2G, it's not all that hard to get them into the 11's with basic supporting mods and a stock engine.

 

[Spleen8urLSX]

14b's also don't live nearly as long above 18lbs as a 16G does(stock for stock. Not talking about upgraded thrust bearings/collars/whatever other magic is done to help the 14B live longer).

Also curious to know what 18G it is. I'd keep whatever you have on the car now, and just build up some parts. Throw on a 16G(if your 18G sucks), some 550's and a Wally 255HP + AFPR, intake/exhaust, and a good ECMLink (or H8/Flashable ECU and tune) and it'll be a very nice street car, that'll get you used to maintaining a modified turbocharged 20+ year old sports car, and how these cars respond to mods. Then when you're an expert and run 11's on the 16G(After replacing and adding things more than just my basic list I gave), you can start upgrading and going bigger from there.


But even with 2022 and all the "tech" we have, you'll never convince me there's a better turbo for a purely street DSM than a 16G. They're just so robust, last so long, so easy to tune with, and their torque hit is ADDICTIVE. That MHI 'you've got....BOOST MOTHAFU**A!!" is so fun. Linear power is fun, sure, but something about the instant hit of a 16G always feels...right. Not to mention even on a heavy 2G, it's not all that hard to get them into the 11's with basic supporting mods and a stock engine.

I’ll still say to this day the 16g is hands down the best “street” turbo, I’ll likely be going back to one when I’m done with the 14b as I have a few scores to settle with the 16g, but I don’t know that I’ll ever go back to a “big turbo”, I’d likely build something else before going down that road again.

 

[CrackedDSM]

I’ll still say to this day the 16g is hands down the best “street” turbo, I’ll likely be going back to one when I’m done with the 14b as I have a few scores to settle with the 16g, but I don’t know that I’ll ever go back to a “big turbo”, I’d likely build something else before going down that road again.

100% agreed. Everyone wants to copy their favorite youtuber or some other internet famous person and make 600+HP, not realizing that on a DSM most 600+ HP setups are gonna be gutless, loud, vibrating, expensive trailer queens because no one builds "Fast with class" anymore. They just aren't fun to drive on the street. To use a methaphor: Everyone wants to be gangster until its time to actually do gangster stuff. Lol.


16Gs FTW. Especially paired with a proper setup. And if you've got E85? Get outta here. Honestly a DSM that runs 11's or even bottom 12's on the street is EXTREMELY hard to beat. Even at the track/test n tunes. So many people have stories that this car and that car runs 6.60's in the 1/4 bone stock and does 0-60 in 0.3 attoseconds, but just go to the strip. Those same cars will run 14's or slower because drivers, conditions, tires, and etc all matter.

Okay, unrelated rant over. Sorry. Lol.

 

[JusMX141]

A cast-wheel 18G is a bit of a dud, hence the reason you got it so cheap. Somewhere on here is a thread where a guy ran a cast 18G back-to-back with an Evo III 16G on the same dyno, and the 16G made more horsepower at the same boost level. Wasn't much, but enough that no cast 18G really has much place on our cars. Performance billet is a different story.

Either way, the stock fuel system can't support more than 26-27lb/min of airflow...so whether you get there with 18-20psi on a TB2566 or 12psi on an 18G you're still hitting fuel cut.

 

[Vegas Smith]

My car came with a cast 18g and I ran it on e85. That was a really fun car that hauled ass. The 16g-style cars have a way of making you think they're faster than they are. It's probably why a lot of people say their favorite car was xyz car with 300hp instead of their 800hp evo. I take stuff like that into account when modding mine. I've thought about downgrading turbos/cams, and I still have memories of when I finally built my "new" red car and how that 18g felt at 30+psi. Sometimes I think I should have never switched.

 

[1997DSMALEX]

Dont mess with it for now. Put the stock turbo back on and start saving for the other parts first.

Basically even if you put in a bigger turbo the computer is locked in its stock configuration. So you would add a bigger turbo and the mass air flow sensor will see it sucking in all the extra air and basically shut off the fuel to prevent the motor from going to unsafe boost levels. Even adding injectors and fuel pump does not change how the ecu sees the air coming in, and the ecu still thinks its a stock eclipse. You will need to buy an ecu sold by ecm link to unlock your computer for programming and tuning. So you have to "tune" the car to accept new values for boost and fuel settings

Some cars are easy. You buy a new mustang gt and call a shop for a dyno tune. Yeah I got a cold air intake and i want the car tuned, sure the tuner says, that will be $800 and ill get you an appointment for 3 months from now

Dsm's have hardlocked computers, the 98-99 cars came with a black box ecu that will accept outside programming if you know a tuner who uses evo scan software. most shops dont offer much service like that for our cars anymore, most shops wont do tuning for these cars. Its not a growing platform and the software isnt widely used across different makes and models, they'd rather charge the mustang guy $800, than charge you $800 and find out you have a boost leak or ignition miss on the dyno and have to scramble around trying to fix random issues that always pop up on older cars

You'll need:
Dsm link ecu and software ($800)
Fuel pump and wiring kit ($300?)
Fuel injectors. Lets say $300
Fuel pressure regulator $120
Turbo install kit $100
Front mount intercooler kit $500

So youre now $2200 into a build to run a $100 turbo.

So lets go backwards, you wait a year and collect all these parts, you gonna want to run the $100 turbo and maybe make 300 hp? Or you want to spend $1100 on a super nice turbo thats gonna make the guy tuning your car sweat balancing fuel data tables on the dyno because that expensive turbo makes a lot more power

The turbo is just one piece of the build

If you really just want some extra fun try to trade that 18g turbo for a nice 14b turbo off of a first gen dsm and have more fun getting to know the process. The 14b will probably gain you about 15-20hp and really change your redline power band. The stock t25 really strugges to make power to redline on those cars and the 14b really makes the car feel like its a hard acceleration to redline

Ok that seems to be my problem currently am I able to tune the mass air flow with ceddymods? I've put in a FP green turbo with new injectors manifold and pump but I've tuned the injectors and I think you're right on the mass air flow system as it shuts off almost immediately on me.