2G Increasing Performance Prior Turbo Spool-up

[jnf63]

I have looked through the Forums and apologize if I missed this one in a related field. Presently, my automatic transmission '95 GSX has a complete air intake, a ported FP big28, a manual boost contoller with its gauge, a ported 2G exhaust manifold, a ported 2G O2 sensor housing, a turbo back 2 1/2" exhaust with high flow cat, a SAFC II, a full intercooler piping with bov, and 550cc injectors. Everything is newly added due to my stock turbo being on it's last few miles, so I replaced it, and added the other modifications, prior to the turbo damaging the GSX. I do not race, but I want to have better highway driving performance and enjoyment. My question concerns getting better initial acceleration from a dead start, or while driving a consistent speed, prior to the turbo reaching its boost level. Are there any adjustments, products, or devices that help with this? My automatic transmission is probably a factor, but I am hoping someone, using their experience/toil, has ideas or recommendations to gain better acceleration than normal. Thank you for anyone that may have input.

 

[David15151]

honostly.. after your mods.. the only thing that would help when off turbo in the range would be .. NOS. Only thing I can think of at the moment that would work.

 

[sjwelna]

honostly.. after your mods.. the only thing that would help when off turbo in the range would be .. NOS. Only thing I can think of at the moment that would work.

It all depends on you budget. You could build a 2.3L stroker motor. That will give you a lot more low end torque.....

-Steve

 

[jnf63]

honostly.. after your mods.. the only thing that would help when off turbo in the range would be .. NOS. Only thing I can think of at the moment that would work.

Thank you for your reply. As you figured, NOS is more than I'm looking for to possibly get better performance prior to spool-up. However, I value your response, and it is greatly appreciated. By the way, your TSI looks great. My GSX is OK, but nothing like your TSI.

 

[river]

go for the 2.3 L stroker kit and some 272 cams. that will give you insane low end as it does in my 1G

 

[rdeterman]

can we please just call it nitrious, or something other than "NOS" anyways.. your 2.0l turbo 4cylinder will never have alot of low end torque you give that up for your high end power... just port everything and try and get that turbo spoolin as fast as possible

 

[L2RTSiAWD]

A stroker motor will give you more low end torque and power.

272 cams will not give you more low end power

 

[jnf63]

Thank your for all the input concerning a 2.3L stroker/kit, yet this would put me in a whole new league of performance that would be more than I desire to spend. I definitely appreciate your suggestions. My desire is to have a daily driver with more enjoyment, your amazing DSMs are show-car quality and race-car bred. Nevertheless, I am open to learning more about what is available for my GSX.

 

[David15151]

very correct. 272 cams would trade your low end to improve your high end power band. you dont want that.

 

[David15151]

also, fill out your vehicle profile so we can help you in the future when you ask questions.

 

[suicidal2af]

Without knowing whether you have a 1G or 2G, some sort of tuning device would help. Advancing timing in the low end and leaning it out some will help a tad.

 

[jnf63]

Thanks for your suggestion about tuning, timing, and leaning. I recently had all this work on my 2G GSX completed (see car profile), including the SAFC II for tuning. I'm still experimenting with the proper adjustments for the SAFC II. In fact, I have another thread inquiring about the most appropriate tuning of the SAFC II related to my modifications. Since I'm not a mechanic, I've had one do all the work for me. He suggested I try to find a resource to aid in tuning the SAFC II properly. I'm not sure if your advise concerning tuning, timing, and leaning meant something like a SAFC II, or if you had other products in mind.

 

[river]

i know that 272 cams would not improve low end torque, but thats what the stroker kit is for. you get mad low end and better top end with the combo of both. if you want just low end, stay on stock cam, or 264s, and get a stroker kit. but depending on what turbo you have the 272/stroker combo can be a mean combo. either way man...low end sucks no matter what in a 2.0...nothing to really improve that a whole lot, except for boosted launches.

 

[pboglio]

jnf63,

You have a 95 gsx, which means crappy low ignition timing right where you need it the most. I run a DSMlink with +5* timing advance from 500-3500 rpm. Big difference in offboost/part throttle power. Stiffer wastegate actuator (Forced Performance or Hahn racecraft). Big difference in how the boost builds up, more part throttle boost and a much much harder hit of boost. Tighten all hose clamps and do an intake pressure test. How is your boost controller hooked up? Is it teed in with your compressor bypass valve? If it is then it "could" be hanging your valve open at part throttle and causing you to have to open the throttle more to get the turbo to spool up. Are you too lean in the 500-2000 rpm range, not good for low end power. I add usually 5-8% more fuel in this range to really give the low end some more kick, then lean out in the 4000-7000 rpm range to get max WOT power. How is your port work on your turbo/manifold. Overporting in the manifold collector/turbine housing is useless on a T28. My 91 automatic did not like an overported 7cm on a 16g, made the low end really mushy. Was your exhaust manifold flycut/resurfaced before installation, could be leaking. Your only sealing with a thin metal gasket, all surfaces need to be really flat for a good seal. Are your manifold/turbo bolts tight, you should retighten when the turbo's hot. And so on, YMMV. Anybody telling you to get a nitrous kit or stroker kit for your level of mods is somebody who needs a crutch to get their car to run right. Your choice. Cheers.

Gene

 

[truwarrior]

You can do a full tune-up. Replace plugs, wires, o2 sensor, check your grounds, clean your air filter, wax it Also recommend cleaning out your combustion chamber with some MCCC or SeaFoam.

Also see if you can pull anything to drop some weight.

 

[jnf63]

You can do a full tune-up. Replace plugs, wires, o2 sensor, check your grounds, clean your air filter, wax it Also recommend cleaning out your combustion chamber with some MCCC or SeaFoam.

Also see if you can pull anything to drop some weight.

Truwarrior,
Thanks for the information about using the mentioned cleaning agents. I am a novice, and I am still learning. These recommendations could definitely help. As for the replacement advice (plugs wires, O2 sensor, grounds) , luckily I had all this done around 2000 miles ago...but I appreciate your suggestion.
The only weight I sometimes wish I could drop out of the GSX would give me a tounge lashing. Seriously... since it's a daily driver, I would need to really use scrutiny to drop anything, but there may be a possibility. Thanks again.

 

[midnght]

The DSMlink suggestions are very valid. But the tuning of the S-AFC II to "lean" it out before boost hits is not a recommendation worth your time. It will yield low results and have you possibly starving the motor before it gets a blast of pressurized air.

You need to find a dyno and rent it for an hour or so. Sit in the passenger side and watch the guy tune your car and have him explain everything. It is your car and you should know what is going on.


The sad fact of a turbocharged engine is the low end. It is going to be less responsive than any other car out there that is N/A or even supercharged for that matter.


Hope I shed some light somewhere.

 

[olmytsi]

get a datalogger to help u tune ur afc. u need the obd2 logger and 1 can be found at http://www.pocketlogger.com/index.php?pid=obdii


peace

 

[G_S_X]

shift higher, after that the only thing that could help significantly is engine internals

 

[90LaZeRrst]

the only place you should be using your AFC to tune is on the dyno. Street tuning is stupid, and will only decrease the life of your car. why not spend around 100 dollars and get your car to its peak performance the easiest way. As for your low end power, Get some good tires, stiffer clutch, and get that turbo spooling as fast as possible. That might be more money than you want to spend, but it would be worth it. However, if you do get a stiffer clutch, get a twin disk to possibly help prevent crankwalk. If you do not know what this is yet, do a search and find out fast because you own a 95 and its VERY prone to it.

and i just realized your automatic. Get a shift kit and have it installed the right way. And as for highway driving, you picked the wrong car for that. AWD is good out the dig, but is a dogg on the highway compaired to 2wd.

 

[90LaZeRrst]

shift higher, after that the only thing that could help significantly is engine internals

wut do internals have to do with shit? . Unless you are talking about boring ( which would help a lil), pistons, rods, etc do not help performance ( unless you change your compression).

 

[jnf63]

Thank you to all those who responded since I last posted.
I shall try to utilize all the information provided and make a much more intelligent decision than I could have prior to my learning from all your DSM knowledge and experiences.

I see now that renting a dyno would be the best choice for tuning. I do know one exists in my area. So, as soon as I get my GSX back from the transmission shop, I shall make an appointment. Presently, I am correcting what I had been told by a Mitsu. Service Center, during recent state inspection, concerning excessive "delayed engagement" of the A/T. Consequently, it had been during this inspection that I learned that my high mileage stock turbo was on its last few miles, leading to all the listed modifications instead of just a new stock turbo. I have learned , on another thread, to add a Translab Shift Kit with valve body work and to use better fluids for accomplishing an A/T cure.

Oh, I guess I shall have to put up with the AWD being a "dog" on the highway vs. the FWD since I value AWD for the winter driving security. I am learning as I go.
Thanks for all the information.

 

[pboglio]

Yeah, the shift kit idea is a good one along with a higher stall speed for the auto tranny. Gives you that nice pop off the line that the 5 speed guys get by launching at a higher rpm. A big ass tranny cooler becomes necessary here. These would have been my mods if I kept my 91 longer.

Gene