Can LT1 valve springs slow a turbo motor down?

[MoeJr]

Stock factory setting for WOT shift is 4800-5000 rpm. U cannot go by stock tach as it reads high at those rpms. The car should be shifting at a true 4800-5000 rpm on an accurate tach. If it is in fact shifting at 5400 rpm you would have to take the governor out of the trans and add just a minute amount of weight to get it back down. I believe B&M makes a governor recalibration kit still. U can also ad weight by just zapping the stock weights with a mig. It is all trial and error though.

Moe

 

[KEVINS]

I agree!
I have the same Kirban springs and the same problem. No matter what I change I can not get over 109 mph. I have gone up/down on boost, changed chips, changed total timing from 24*, 26*, 32*, shift rpms, changed fueling, locked/unlocked the converter at different times, etc.. No matter what I change it will not MPH over 109 and the car is way off to what people say it should be the last 1/8 mile. I have changed too many variables NOT to see somethign change for the good or worse. I plan to change springs again before I go racing again..

ks

 

[VadersV6]

I agree!
I have the same Kirban springs and the same problem. No matter what I change I can not get over 109 mph. I have gone up/down on boost, changed chips, changed total timing from 24*, 26*, 32*, shift rpms, changed fueling, locked/unlocked the converter at different times, etc.. No matter what I change it will not MPH over 109 and the car is way off to what people say it should be the last 1/8 mile. I have changed too many variables NOT to see somethign change for the good or worse. I plan to change springs again before I go racing again..

ks

Try a few things to improve flow with what you have. I saw a 6psi gain between the dutt neck IC, sawing off the rolled lips on the up-pipe, going with a 3.5" intake tube, and bellmouthing the IC inlet and outlet. Opening up the last 1.5 inches of each intake runner made a very nice improvement. Given the huge taper of those runners, just opening up the exits in effect opens the whole runner. A gasket match on a non tapered runner is pointless, but a gasket match on this intake can make a serious improvement in flow. I also ground a small chamfer on all the intake ports on the heads. Sharp edges are disastrous to air flow. There are alot of little "blueprinting" things you can do to improve power quite a bit. Try getting creative and you'll find those 11 second timeslips.

 

[KEVINS]

Try a few things to improve flow with what you have. I saw a 6psi gain between the dutt neck IC, sawing off the rolled lips on the up-pipe, going with a 3.5" intake tube, and bellmouthing the IC inlet and outlet. Opening up the last 1.5 inches of each intake runner made a very nice improvement. Given the huge taper of those runners, just opening up the exits in effect opens the whole runner. A gasket match on a non tapered runner is pointless, but a gasket match on this intake can make a serious improvement in flow. I also ground a small chamfer on all the intake ports on the heads. Sharp edges are disastrous to air flow. There are alot of little "blueprinting" things you can do to improve power quite a bit. Try getting creative and you'll find those 11 second timeslips.

Did this:..going with a 3.5" intake tube
Did this:..and bellmouthing the IC inlet
Did this including the headers:..Opening up the last 1.5 inches of each intake runner made a very nice improvement.

..among a bunch of other secrets to help get air in and out of the motor but it's still stuck at 109mph.. I even tried an odd ball RA107 chip programmed for a TE44 for very high boost and it still only went 109. The only thing I didn't do was install a big neck on my stock IC because I wanted 11's on the stock IC and others have done it. NOW I have a CAS V4 on it which should get me there but I still think the v-springs are my biggest problem. Either the IC is that much of a restriction (bottle neck) which I don't think it is or there is something not working correctly like the v-springs. I can't find my time slips but if I remember correctly I was only gaining 11 mph the last 1/8 mile on all my runs which is way off from what it should be doing especially when running a 12.1's @ 109.

I just wanted to post and mention that I also think my Kirban springs are bad on my car and will be changed before I go out next time.

ks

 

[VadersV6]

You need to lock that converter up. I didnt even notice where you said you werent locking it. Your mph difference in the last 1/8 shows the converter is probably slipping alot. You could probably try a different converter as well.

 

[KEVINS]

You need to lock that converter up. I didnt even notice where you said you werent locking it. Your mph difference in the last 1/8 shows the converter is probably slipping alot. You could probably try a different converter as well.

Been there, done that... I've tried it locked and unlocked. I locked it at several different times and gears, etc and no difference at all in MPH or ET and you could feel/hear it lock when it was activated so it was working and watching the runs on DS indicate the converter is working great..
Between the CAS V4 and new v-springs I'm sure I will have eliminated the problem and it will finally hit 11's but it'll have to wait till next year. Thnx for all the suggestions tho!

ks

 

[RobV6]

Been there, done that... I've tried it locked and unlocked. I locked it at several different times and gears, etc and no difference at all in MPH or ET and you could feel/hear it lock when it was activated so it was working and watching the runs on DS indicate the converter is working great..
Between the CAS V4 and new v-springs I'm sure I will have eliminated the problem and it will finally hit 11's but it'll have to wait till next year. Thnx for all the suggestions tho!

ks

Also agree on lockup. Had a GN, Stolen tried both ways got better times on the lock up JMO> Also have a Question if it's OK?
. What springs do most of you use on a stock block car.
And where can I obtain them.Sorry for the ignorance. BUt just got hit with the loss of a motor I was buying. So I would like to get the one in the car,
up and going so I can see what Ineed..TIA....Rob

 

[VadersV6]

I dont see how thats possible to see no improvement at all when locking the TC. Your TC, unlocked isnt going to be 100% efficient. Dont count on the TC being perfect. There are people running 14's who should be running 12's. They swap converters and suddenly they dropped 2 seconds of their ET. I wouldnt rule out trying a different TC all together.

 

[Double-L]

Lockup might be better but my tranny was moded for a 9'' art car no lock and for a stock block car it doesn't run to bad, Best of 11.17 et on gas and 120 mph. Not in that order, Not to bad for a car you can drive to the strip and home with the a.c on, I haven't owned the car that long but wasn't to long ago guys were telling me the only way to go is no lock with the art car shift kit??

 

[Tom87GN]

You need to lock that converter up. I didnt even notice where you said you werent locking it. Your mph difference in the last 1/8 shows the converter is probably slipping alot. You could probably try a different converter as well.

Yep, I've done all of this before. I have locked the converter only to see the MPH the same at the big end as if I didn't.

Recently, I swapped converters out due a "noisy" issue that I couldn't stand. I had a 3200 stall and went with the same stall in the new converter. Completely different manufacturer, same results. My trap speeds and 1/8th mile numbers are virtually the same. So I have to believe that my converter is doing what it should, would you agree?

I think what I may do here is swap out the valve springs for some 980's and replace my ET Streets with some 28"-29" ones. Hopefully that will get me into the 11's with my combo.

Thanks to all for the awesome information and advise!!

 

[UNDER-PRESSURE]

The 28" tire is what your combo is missing. You will be able to shift your stock cam engine around 5,000 rpm & pull THROUGH the lights in 3rd gear in your engines powerband. The worlds greatest trick valvesprings will not extend the usefull power range of the stock cam. Just because the engine can spin past 5,400 rpm does not mean it's making power. I agree with your results on the locking of the converter. You may not see any gains because you are maxed out of rpm at the end of the 1/4 mile. Many cars hit this wall around 110 mph & need to make the jump to taller tires. You can either change tires to get your rpm's in check or find a shorter track.

 

[Ed Valvo]

When locking, there is such thing as locking it up too early and bogging the engine a bit until the RPM's get back up. Try experimenting a few runs and monitor the RPM drop. Try not to let it drop below 4000 RPM after the convertor locks up. RPM drops will vary on convertor and actual power you're producing.

 

[Tom87GN]

The 28" tire is what your combo is missing. You will be able to shift your stock cam engine around 5,000 rpm & pull THROUGH the lights in 3rd gear in your engines powerband. The worlds greatest trick valvesprings will not extend the usefull power range of the stock cam. Just because the engine can spin past 5,400 rpm does not mean it's making power. I agree with your results on the locking of the converter. You may not see any gains because you are maxed out of rpm at the end of the 1/4 mile. Many cars hit this wall around 110 mph & need to make the jump to taller tires. You can either change tires to get your rpm's in check or find a shorter track.

Good point, UNDER PRESSURE. I will definitely be wearing 28" tires next season. I have to believe that my motor is running out of cam at the big end. My goal has always been to run 11's with the stock motor, so if the tires are the biggest part of what's left in this combo, that's what I'll be changing.

Time to let the wifey know that she needs to leave some room under the tree for some 28" Mickey T's for Christmas this year!!

 

[Tom87GN]

When locking, there is such thing as locking it up too early and bogging the engine a bit until the RPM's get back up. Try experimenting a few runs and monitor the RPM drop. Try not to let it drop below 4000 RPM after the convertor locks up. RPM drops will vary on convertor and actual power you're producing.

I understand the issue here. I know that my converter wasn't locking with my Red Armstrong chip until near the big end of the track each time. I never thought that it was bogging down the motor, but then again, I didn't have my computer on at the time. I was just watching the knock on my scanmaster.

Thanks for the info!