Can LT1 valve springs slow a turbo motor down?

[Tom87GN]

I installed a set of the LT1 valve springs on my otherwise completely stock turbo motor about 5 years ago. This was during the craze where all the turbo vendors were saying that these were the springs to use on the turbo motors.

I had a spare set of these springs tested for open and closed pressure ratings and they were all over the board, varying from top to bottom by as much as 20 lbs of seat pressure.

My question is this: could the installation of these LT1 valve springs hurt my performance?

The reason that I ask this question is because I have been fighting the fact that with all the parts in my signature below, I still can only achieve 109-111 mph in the 1/4 mile. With the parts, I've been told that I should get 113-114 mph.

I hit 111 mph just a month ago with this combo, which is the fastest that it has ever gone, so I most likely isn't because the springs are old and need to be replaced. They probably only have 20K miles on them since they were installed.

My goal is to get this thing to run a high 11 second pass without having to port the heads or add an aftermarket camshaft. I know that this can be done, since so many others have succeeded.

Thanks for any ideas and/or assistance in advance!

 

[TurboDave]

Your sig includes a street chip, but makes no mention of a race chip. Based on the rest of the parts, and your desire to run in the 11's at over 113 are a bit unrealistic with a street chip, but should be obtainable with a good race chip, good gas (octane 112+) and sticky tires.

 

[VadersV6]

How many times have you over revved it and floated the valves? Thats a hard question to answer, but every time you do it, you're killing the springs. Most shops install LT1 equivalents...same goes for most springs. They're just equivalents of the real thing. But in reality cant retain their pressure for as long as the real GM stuff. When I get springs, Im going beehive. No reason whatsoever not to. After 20k miles, I would replace them.
How much boost are you running? Are you tuning yourself or at the mercy of a mail order tune? I dont know much about the chip you're running. A street chip and alky by nature is a self defeating combo. With alky you want high boost and high timing. Extender chips rock! I can tune it all myself with an A/C lever, a parking light and a gas pedal.

 

[Tom87GN]

Your sig includes a street chip, but makes no mention of a race chip. Based on the rest of the parts, and your desire to run in the 11's at over 113 are a bit unrealistic with a street chip, but should be obtainable with a good race chip, good gas (octane 112+) and sticky tires.

Thanks for the reply, TurboDave. I have run a race chip in the past with this same combo. I have run a race chip from Joe Lubrant as well as Red Armsrtong with about the same results. Actually, I achieved the same times running Joe's street chip that I had in the past with the race chips.

I always run 108-110 octane fuel and I have ET Streets that I use at the track. I don't get any knock with this fuel in the tank, usually.

My short times could be better, but currently they range from 1.75 to 1.90 depending on how bad of a driver I decide to be. I'm not a pro at launching this car, that's for sure.

 

[Tom87GN]

How many times have you over revved it and floated the valves? Thats a hard question to answer, but every time you do it, you're killing the springs. Most shops install LT1 equivalents...same goes for most springs. They're just equivalents of the real thing. But in reality cant retain their pressure for as long as the real GM stuff. When I get springs, Im going beehive. No reason whatsoever not to. After 20k miles, I would replace them.
How much boost are you running? Are you tuning yourself or at the mercy of a mail order tune? I dont know much about the chip you're running. A street chip and alky by nature is a self defeating combo. With alky you want high boost and high timing. Extender chips rock! I can tune it all myself with an A/C lever, a parking light and a gas pedal.

Over reving would be what RPM? I usually don't get the motor over 5400 RPM before it shifts. Is that too much?

I usually run 21 psi on the street with the alky on, at the track I usually end up bumping it to 24 psi or so.

I am tuning myself with the help of a few knowledgable TR friends. I'm not the best at tuning, thats for certain.

I've heard about the Extender chips, but never really gave it another look. Do you think if I got set up with one of those I would be better off with trying to attain the 11's?

 

[VadersV6]

The extender chips are run with an LS1 MAF and LS1 MAF translator, so you'd have to go that route, although I think they have the commander chip now which doesnt require a translator...dont know if they require the LS1 MAF even.Would be nice for alot of people if you could run the stock MAF with it. Running it to 5400rpm doesnt sound like much, but if the springs are tired, theres no telling at what rpm the valves will float. You can tell by looking at a dyno graph. Have you ever over revved it at all?

 

[my 1st gn]

we almost have the same combo an mine ran the times an my sig at 25psi an 26 degrees of timing with a joe lubrant race chip

 

[Tom87GN]

we almost have the same combo an mine ran the times an my sig at 25psi an 26 degrees of timing with a joe lubrant race chip

You've got me by 6 mph!!?? You have stock unported heads and stock exhaust manifolds? Are you launching on the foot brake to get the 1.60 short time?

Sounds like I need your help tuning my car!!

Seriously, what do you think my issue is? I don't think I have an exhaust leak, but my O2's always sink into the mid to low 700's at the big end of the track. I have run a Joe Lubrant race chip before with not so impressive results. Something.......even minor.....is keeping my GN from attaining the mph that it should with the parts I've got installed.

 

[Tom87GN]

Have you ever over revved it at all?

I'm not even sure I could tell you what an over rev condition would sound like or feel like...... I know I should know this, but I can't say that I do.

What would an over rev condition feel like or sound like? I have a scanmaster for watching the critical numbers, and an old TurboLink that I could hook up to scan the RPM's.

 

[gmpower6]

Tommy Tommy i have an extra set of 980's springs if you need them. Give me a call 217-662-2156.

Later Dog

 

[Tom87GN]

Tommy Tommy i have an extra set of 980's springs if you need them. Give me a call 217-662-2156.

Later Dog

I may just take you up on that offer. I've been suspect of those damn LT1 springs for a while now. Let's see how the rest of this discussion goes and if anyone else gives me any good advise on what they think may be my issue.

Thanks again, Dog. You da man with all the Buick parts!!

 

[MoeJr]

Try shifting the car earlier. That cam is done making power long before 5400 rpm. Try it shifting at 5k.

 

[my 1st gn]

You've got me by 6 mph!!?? You have stock unported heads and stock exhaust manifolds? Are you launching on the foot brake to get the 1.60 short time?

Sounds like I need your help tuning my car!!

Seriously, what do you think my issue is? I don't think I have an exhaust leak, but my O2's always sink into the mid to low 700's at the big end of the track. I have run a Joe Lubrant race chip before with not so impressive results. Something.......even minor.....is keeping my GN from attaining the mph that it should with the parts I've got installed.

1. heads are stock
2. exhaust manifolds are stock
3. valve springs are from kirban
4. poston's timing chain
5. 10lb launch off the foot brake, rjc's boost controller and poston's rear brake shoe upgrade can = stock axle breaking launches ask me how I know

 

[Tom87GN]

Try shifting the car earlier. That cam is done making power long before 5400 rpm. Try it shifting at 5k.

I understand what you are saying here, but I can't do what you are referring to (I think). I leave the car in "D" and just go. If I shift it myself, it will still do what it would normally in "D" correct?

 

[Tom87GN]

I think all of this information is great and I appreciate all the informative responses. It looks like what I may need to do is swap out my LT1's with a set of stocker 980's. This is what I was leaning towards all along, I just needed to hear from others that this may be my issue.

 

[UNDER-PRESSURE]

What RPM are you running at through the lights? Are you locking up the converter? What size rear tire?

 

[Ormand]

I agree with MoeJr that the stock cam is out of its range by 5400. Don't know what the governors are set at in the transmission, though, but I think it's something less than 5400.

 

[Double-L]

I just leave mine in over drive and it shifts at 51 to 5300, I am in over drive when I cross the line, Have $2.39 street springs and run a best of 120 mph

 

[Tom87GN]

What RPM are you running at through the lights? Are you locking up the converter? What size rear tire?

I don't get over 5400-5500 at the lights with the stock motor. I am guessing somewhat here, though, because I haven't put my TurboLink on the car in over a year. Maybe I'll take it out tonight with the computer on it and see where it's shifting. If I do this, I'll report back to this thread with the results.

I am not locking up the converter, although I did have that option on my Red Armstrong chip last year. It did me no good with the MPH thing.

The tire is an ET Street 26.5 x 11.

 

[UNDER-PRESSURE]

Your probally ready for a 28" tall tire. That change should have your stock cam engine pulling through the lights instead of being at or past it's usefull powerband. Swap tires & lock that convertor & your car should fall right into the 11's.