Thinking about going from 18g to Big 16g...

[usmc0651dns]

I have been trying to decide whether I should trade my 18g kit for a big 16g. I'm looking to get around 350 HP on a daily driver GSX. What do you guys think?

 

[purewake07]

If you do, i would highly suggest porting it, along with the o2 housing and exhause mani. That will give you the quick spool-up and higher rpm power.
Ive never had a 18g but i <3 my 16g. Whats the matter with ## 18? Seems like a good fit if you want to run 350 hp all day

 

[dsmdeliveryboy]

Don't do it, the 18g makes awesome power. I'm running a fully ported FP18g and it pulls hard even at 17psi(I have it at 20psi). The 18g doesn't really get in its power range until after 21psi anyways though, GL with your decision.

 

[usmc0651dns]

Thanks for the info. I guess it would be better to use less potential on my 18g than to try and max out the 16g. When you are running 17 or PSI does the turbo lag or does it spool decent compared to the 16g? I just bought a GSX with the 18g and haven't been able to drive due to other issues. I'm going to start tuning with Link tomorrow and hopefully get it running decent. So spool? I was hoping to set it at 15 PSI and then on 20-25 PSI for weekends.

 

[JusMX141]

When you are running 17 or PSI does the turbo lag or does it spool decent compared to the 16g?

The lag difference between a Big 16G and 18G will barely be noticeable; similar to going from an 18G to a TD05H 20G.

I was hoping to set it at 15 PSI and then on 20-25 PSI for weekends.

You feel like going faster on the weekends?

I'd just get it tuned, and run the max boost you feel comfortable with all the time. For a 2G 7-bolt with stock head bolts, around 22psi seems to be comfortable.

 

[usmc0651dns]

Head and motor is good for up to 1000 HP from what the machine shop said. Yeah I live in a small town and they do races on weekends so that's when I would want to turn it up. I think I'll just keep the 18g and tune it to about 25 comfortably.

 

[the_mork]

Turning up the boost on the weekends or running two different boost levels is silly to me. Control boost with your foot. If you don't want to boost 20psi then don't push into it so far.

A street and race tune I can see though as I'm more willing to run leaner AFRs and borderline dangerous timing at the track than on the street. But then again with a good tune that is stable it probably isn't necessary to switch that either.

 

[toofast82]

I've ran both a tdo5h 18g and big16g. They both performed VERY similarly with the 18g having slightly better high boost performance(~23psi+).
Since it sounds like you already have the 18g, I don't see any reason to switch out to a 16g.

 

[JusMX141]

Head and motor is good for up to 1000 HP from what the machine shop said.

Does your machine shop realize what needs to go into a 4 cylinder in order for it to make 1000hp?

 

[superorange]

Does your machine shop realize what needs to go into a 4 cylinder in order for it to make 1000hp?

I was just going to post that , to the op just be careful of what "small town" shops you bring that thing to, a lot of them dont know anything about turbo cars, just diesels and v8's .