top end mods

[jerzeytib]

I have a gs-t and I'm not really concerned about the quarter mile time. I just want to know what mods would yield a very strong top end car. Also, my current whp goal is 250-275,

 

[c5chris]

Nothing but a turbo will give you top-end acceleration - of course it includes the supporting mods.

For your goal, a small 16G or a T28 will be sufificient.

 

[eclipsegsx9797]

well depending on what money u wanna spend u could get a nice full garret 60 or 60-1 trim turbo or even a bolt on turbo. this turbo will give you crazy top end. to add to this turbo you could get a magnus intake manifold or any other type of i/m that impoves the intake side, and some hks 272' cams. with these 3 things and supporting mods your top end will hang with them crazy supra's on the highway. well some of them

 

[mitsuclipsegsx]

get the evo one

 

[Turblown]

You'll be surprised...
alot of people will say "get this turbo or that turbo" and then mention to of course get "the supporting mods."
I'm a firm believer in the performance capabilities of the 14b (stock turbo)
While a turbo like a 16g will be more efficient and a bit more powerful.... the supporting mods done to the car before the turbo upgrade will add alot too....
I don't have any numbers (yet).... but IMO you could reach at least 250whp with just supporting mods...
IMO its worth it to put some money into getting the most out of your stock turbo... and it will make the transition into a new turbo that much easier... on you and the car.

For more top end power you will definitely need a bigger turbo... but you don't necessarily need a bigger turbo for 250-275whp.

just my 2 cents

 

[midnght]

The 14b has produced a dyno run of 277whp. I have seen it with my own eyes.

Just get the proper support for it.

Type a search for "fastest 14b" or a variant of that. They all have been in the low 12's with this turbo, even though you said you are not worried about 1/4 miles, you can get a good idea of what your stock turbo can do.

 

[jerzeytib]

Thanx

 

[kpt4321]

What do you mean by "top end." Do you mean trap speed in the quarter mile (80-120 mph) or highway races (80-140 mph) or faster highway runs?

The main place you can improve for top-end performance is the engine's breathing at higher speeds (engine speeds, not ground speeds). In stock form, the 4G63 is going to lose a lot of power above 6000-7000 rpm, simply because it is factory tuned to offer more torque and driveability in the middle of the powerband.

If you are aiming for 250-300 whp, that can be done with the 14b. However, even with the stock turbo there are gains to be made with regard to higher speed and higher rev performance.

The simplest mods are opening up the intake and exhaust stream; a good filter, intake piping, and a high flow intercooler setup are key, as is a good high flowing exhaust. Nothing will kill the performance of a turbo car more than a restrictive exhaust.

Then you start doing some work to the top end of the motor. Cams are also a VERY big improvement to top end power, I have seen people gain 20-40 horsepower at the 300 horsepower level, just from switching to HKS 264 or 272 cams. That's huge!

After than, you get into intake manifolds and headwork.

People who are suggesting things like a 60-1 are crazy. If you want to make 300 whp, a 60-1 is not going to help you much (if at all!) with top end performance, not any more than a 50 trim would, and not a whole lot more than a 16g.

 

[jerzeytib]

I was talking about 80-140 runs and you basically covered it for me.

 

[midnght]

I was talking about 80-140 runs and you basically covered it for me.

Kyle is very good with a DSM. He knows his stuff. If you get him to respond to a post, listen. This will get you along pretty well. I know he has helped me out before with NO smartass comments. Several times.

 

[DSMNightmare]

If your going for top end your going to want to have quite a bit of hp. First you can obviously go with a bigger turbo for top end but you also will want to consider HKS cams and a sheet metal intake manifold. Magnus sells one of the best.

The thing about top end is these cars are limited to about 175mph and I do believe that is with the rev limiter moved 500-1000rpm. The ~175mph is the limitations of the gears in the tranny. TRE sells a big top end gear that is supposed to be good for ~208mph BUT you have to think that when you start reaching a certain mph in a DSM your not just fighting gears or airflow but also drag and downforce are going to play a part. You do not want to be crossing 200mph with stock suspension or stock ride hight. You also going to need enough hp to fight the the drag created by your car cutting through the air.

If your just shooting to be good at about 140-160mph then you should be fine doing the upgrades that other peole have mentioned. Also remember at those speeds you do want to make sure the car is properly tuned for those conditions. Dyno's run your hp through 3rd gear which is nowhere near the top end of your car. You would want to dyno tune your car for top end so you don't peak out your EGTs and lock up your motor.

Just some things to think about. Basically if you want good top end your going to make a lot of similar mods that you would for a good 1/4 mile.

 

[DSMNightmare]

I was talking about 80-140 runs and you basically covered it for me.

Oops saw this after I posted. You should be good with a 20G and Cams to get you from 80-140mph fast. The sheet metal intake would definately help but it's not 100% necessary. Before my sheetmetal intake the car would pull 140mph without breaking a sweat.

 

[jerzeytib]

Thanx alot to everyone that has helped me

 

[Kandy_GSX]

It all depends on how much money you want to spend.
1.Forced Performance Green, any 50 trim, 20G, etc etc
2.All supporting mods for turbo
3.HKS 264/272 cam combo (assuming you want your car to be more streetable) If not, go with the 272/272 cam combo. You should yield better top end results with them.
4.Forrester makes a nice intake manifold
5.And a lot of tuning
Even with all this, your not only gonna have a top end monster, your gonna have a pretty wicked drag car. Assuming you can drive it, and get traction.

 

[DSMKevan]

Please god make sure your tires are rated at the speed you want to go!! If they arent...youre screwed...literally.