Engine/Transmission (1994 - 1998) GSK for my 12v?

[JHenry]

I have added a #5 TST fuel plate to my '98 12 v. I also have added 4" MBRP straight pipe and AFE stage II filter. I have added a BD valve body and triple disc torque converter to the stock transmission. The truck is very lively from a dead stop, and has plenty of low end power. My question is: How much will I benefit by adding a 3000 rpm spring kit? Where specifically will the gain be noticed? Thanks. JH

 

[Missouri Mule]

The 3000 GSK would be top end as the kit allows the engine rpm to reach at least 3600 rpms. Where the stock springs only allow engine rpm up to 3000 rpm but a lot times stock is less than 3000 rpm.

It will also depend on design of the #5 palte.

 

[biggy238]

Put it in and enjoy it. The truck will be a different animal. I love digging in 3rd from 1800-2500 under full power. Mine would start to defuel at 2100 and fall dead by 2600 or so.



I think it's easier on the trans to rev a little higher between shifts with my tire diameter





Edit: thats not to say at all that it won't pull up through 3000. I just don't have the balls or the turbo for it yet.

 

[tgrfan2]

I have added a #5 TST fuel plate to my '98 12 v. I also have added 4" MBRP straight pipe and AFE stage II filter. I have added a BD valve body and triple disc torque converter to the stock transmission. The truck is very lively from a dead stop, and has plenty of low end power. My question is: How much will I benefit by adding a 3000 rpm spring kit? Where specifically will the gain be noticed? Thanks. JH

Fourth best thing I did to my truck after KDP, DTT, and the plate.

 

[JacobsD]

My opinion is it's the best 100 bucks you can spend on a 12 valve. Especially with a manual transmission. I'm not sure how an automatic reacts to it but I know its nice holding on to that 3rd gear up to about 2800 on my standard shift one with a heavy trailer on the back.

 

[GrantP]

I have added a #5 TST fuel plate to my '98 12 v. I also have added 4" MBRP straight pipe and AFE stage II filter. I have added a BD valve body and triple disc torque converter to the stock transmission. The truck is very lively from a dead stop, and has plenty of low end power. My question is: How much will I benefit by adding a 3000 rpm spring kit? Where specifically will the gain be noticed? Thanks. JH

I noticed a huge difference in highway performance. My truck (with 3. 55 gears and stock tires) was beginning to defuel around 75 mph. This made passing on a two lane road a lot longer than it needed to be. If you tow, you can lock out OD on long hills and have enough RPM's in third to pick up enough engine speed before shifting into OD. Mine was defueling in 3rd, then I'd let it shift into OD only to have the EGT's blow through the roof because of the RPM drop.



I love my GSK except for one day out of every year... emissions testing. The local emissions morons use the "snap idle" test. Your governor won't stop the engine at 3k anymore with the new springs. If you don't have any emissions testing, I'd say there is zero downside...

 

[CTD12V]

I love my GSK except for one day out of every year... emissions testing. The local emissions morons use the "snap idle" test. Your governor won't stop the engine at 3k anymore with the new springs.

Grant, how does the snap idle test work? We have a 60-40 mph lug down test here in Colorado Springs. I don't think a GSK would affect that if I installed one, but I don't know?



CTD12V

 

[GrantP]

The snap idle test requires you to run the engine at full throttle while in neutral for ~ 5 seconds, that process is repeated several times. Why they want to test the emissions of my truck at 3k RPM is beyond me, the only time the tach ever goes that high is at the emissions station!

Anyway, sounds like your test is completely different.

 

[CTD12V]

The snap idle test requires you to run the engine at full throttle while in neutral for ~ 5 seconds, that process is repeated several times. Why they want to test the emissions of my truck at 3k RPM is beyond me, the only time the tach ever goes that high is at the emissions station!



Anyway, sounds like your test is completely different.

Yeah, that is a wierd test for emissions. Ours loads the engine to full boost, which obviously screws up anybody who may be overfueled, or have egt issues at max fueling. And they nail you if you have a straight-pipe without a cat on a truck that originally came with one.



That is why I am worried about turning up my truck, because the blasted emissions test throws a monkey wrench in everything. #@$%!#@$%!



Anyways, I guess this is somewhat off-topic.

 

[GrantP]

I have the same cat problem, I'd love to go to a 4" exhaust but it doesn't seem like anyone makes one with a cat. I can't pass the visual inspection without it.



Judging by your description of the emissions test, it seems like you could easily get away with a plate and GSK. Just tighten the AFC screw prior to the test. My truck is an absolute dog with zero smoke when I tighten the screw a bunch. Just a thought... .

 

[edgeman]

MBRP should make a 4 in. pipe with cat for your truck... all though I don't know... where I live there is no emission testing! Go Blue... . the only way we know the trucks are true is if they don't have spark plugs and throw black smoke.

 

[Bob4x4]

It is simple enough to modify the stock cat to work on a 4" system. I just cut off the 3" end and weld on an expanded 4" end. For the emmisions testing do they inspect close enough to find a valet system?



Bob

 

[biggy238]

ditto on the afc. slide that dude all the way to the rear and choke off the boost signal. Never let it fuel for them.

How can they apply new emissions standards to vehicles that were EPA tested from the factory? That's what the CPL number is. A Controled Parts List that together is EPA certified.



Most of it is a crok of **** anyway. "Here, pay my buddy down the road to er, um, FIX your truck, and we'll TEST it again and you should be alright. "

 

[CTD12V]

It varies on how close they inspect the emissions system. The older style of form they used to use had a box to check off for inspecting the aneroid (afc) for seals intact and no signs of tampering. This last year they gave me grief over my cat not being in the stock location, because the other shop in town that nailed me for not having a cat several years ago installed the new one up stream of the heavier guage pipe that was used by the previous owner to replace the old cat. So if they know enough to spot that, I'm always worried that if they see a 4" system on my truck and a modified factory cat on it, they are going to screw me. I HATE THIS STUPID "CLEAN AIR" CITY! #@$%!#@$%!#@$%! Ok, sorry, I just had to get that out. :-laf



Doesn't sliding the AFC housing back and tightening the starwheel simply control smoke (fueling) before boost comes in? Our test is basically a measure of smoke at peak fueling -- 60 mph lugged down to 40 mph in 4th gear (direct drive) -- so the plate is probably the thing to slide back, right?



CTD12V

 

[Bob4x4]

If you block off the boost signal to the afc the fueling will not increase with boost.



Bob