Boost drops off? I need a drink..anybody?
Boost drops off? I need a drink..anybody? Just finished installing the STS, got it tuned 
423HP 400TQ @ 4 lbs. Frankly....little less than expected, and Getting a little discouraged. last time I did heads, cam, LS6 intake and headers and got 382 HP tuner said "I've seen cam only cars do better"....greeeeat 
and more Now I put put on the STS and I hear "I've seen head cam cars do better" 
I seem to get alot of negative on cam (224 581 114) I guess average for N/A worse for turbo.
Anyway I was told "more boost" so I am ordering WG springs (7 and 8 lb.) but in the meantime, I notice that when I hammer it, at around 3k to 3.5k the boost gauge shoots to 4-5lbs. at around 5800 it starts to drop off. Is it the fact that my engine is drawing everything the turbo is putting out? Thanks and oh yeah
423HP 400TQ @ 4 lbs. Frankly....little less than expected, and Getting a little discouraged. last time I did heads, cam, LS6 intake and headers and got 382 HP tuner said "I've seen cam only cars do better"....greeeeat and more Now I put put on the STS and I hear "I've seen head cam cars do better" I seem to get alot of negative on cam (224 581 114) I guess average for N/A worse for turbo.
Anyway I was told "more boost" so I am ordering WG springs (7 and 8 lb.) but in the meantime, I notice that when I hammer it, at around 3k to 3.5k the boost gauge shoots to 4-5lbs. at around 5800 it starts to drop off. Is it the fact that my engine is drawing everything the turbo is putting out? Thanks and oh yeah
I have considered the possibility of a leak, I did a visual check today, nothing is obvious, I have an EVAP smoker and will smoke the entire system ASAP.
I have a boost controller on order, but have since read that the spring is more predictable? Any other insight into the spring VS. controller would be great....Thanks
I have a boost controller on order, but have since read that the spring is more predictable? Any other insight into the spring VS. controller would be great....Thanks
If you use the boost controller reference your vacuum/boost at the intake or brake booster, you will get a lot better waste gate function if you do. Just run a vacuum line up front. Any more specs on your setup? FMIC?
Originally Posted by zapp168
423HP 400TQ @ 4 lbs. Frankly....little less than expected, and Getting a little discouraged. last time I did heads, cam, LS6 intake and headers and got 382 HP tuner said "I've seen cam only cars do better"....greeeeat
Maybe he should look at the average HP (area under the curve) and not just the peak number before making a dumb statement like that.Your gears are definately hurting your performance as well, switch to something closer to the 3.4x range if you can. My car had 4.10's at one point and it really sucked with the turbo. You can probably only go to 3.73's since you have a 12 bolt though. Cam choice is fine, I ran a 224/224/112 .567/.567 in mine with the turbo setup a long time ago and it worked just fine.
Your numbers are fine for 4 psi, took me 6-7 psi unintercooled with the t67 to get 430 HP out of my setup when I had the stock motor with the 224 cam.
As for boost dropping, do a pressure check and find all the leaks.
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Boost should not be dropping off. A visual inspection will probably not be enough. I would suggest putting tbolt clamps on all intake pipes. Stock, my kit came with regular screw clamps for pipes that were not visible.
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First let me say this...The tuner is a GREAT guy and is THE top notch, and very helpful, if he says the tune is correct then I believe him 101 percent. He actually pointed out that my plugs were wrong and let me stay and change them when he had places to be, he could have just said "too bad" The comments were more "matter of factly" and he probably meant to just compare, I just get a little discouraged. Been working too much lately and it takes it's toll.
As for my setup....I have a FMIC and 60 lb. injectors. I referenced the wastegate at the booster and ran a line back. As for the tune, I should write down more info, but the problem is not the tune, it is me somewhere. I am going to smoke check the intake side, I have screw clamps on everything, I have planned to upgrade. I know the gears are hurting it, alas I only have time for one mess at a time..
Thanks for the encouragement, I will resume plugging away at it
As for my setup....I have a FMIC and 60 lb. injectors. I referenced the wastegate at the booster and ran a line back. As for the tune, I should write down more info, but the problem is not the tune, it is me somewhere. I am going to smoke check the intake side, I have screw clamps on everything, I have planned to upgrade. I know the gears are hurting it, alas I only have time for one mess at a time..
Thanks for the encouragement, I will resume plugging away at it
I agree with the posts above, 430 RWHP at 4 PSI seems right on to me. One of my Maggie setups ( non I/C ) made 430 RWHP at 5PSI, so I think you're making good power for the amount of boost that you're seeing. I agree that you probably have a leak somewhere, make sure all of your clamps are very tight. Don't just look at them, put a tool on each one and try to tighten it. If all of the clamps are tight, then check all of your ductwork very closely, you may have a small cut or something in one of the silicone couplers.
Hope this helps,
Ed
Hope this helps,
Ed
Agree with all above, 430whp @ 4psi isn't bad at all.... and since you have everything else at your disposal (good rear, good fuel system, fmic) there's nothing stopping you from taking it up to 7-9psi sans an MBC. 5 more psi should net you 90-125 more rwhp than you make now. And to underscore this as well, ditch the 4.10s.... it sucks that to get back to 3.42 or lower thatr you would have to replace the whole carraige 
You need to check for leaks intake and exhaust. I made some tools for checking the intake side from home depot and a tire schreader valve! Pumped up to 20psi and found a bad weld near my wastegate. Also my exhaust didn't sound like it was leaking at idle, but I capped the tail pipe for a second and got a whistle out if the y-pipe joint. STS turbos run a 2:1 to a 3:1 pressure ratio. so you have between 8-12 psi in you exhaust pipes
Originally Posted by Zombie
Yeah, great dyno operator Maybe he should look at the average HP (area under the curve) and not just the peak number before making a dumb statement like that.
.
Maybe he should look at the average HP (area under the curve) and not just the peak number before making a dumb statement like that..
I was busting Zappa's ***** like ussual.Mostly because he had only 4lbs of boost.The car was not what I expected since it made 380rwhp before the STS but we both know the boost needs to be turned up to 8-10lbs to see a big increase.
As for the boost controller -nothing special is needed,just look at STS's site and get the cheap looking controller which is prettty much a regulator.It works extremely well and is cheap.
Originally Posted by Slowhawk
Thanks,I'll take that under consideration when I tune a car next time
I was busting Zappa's ***** like ussual.Mostly because he had only 4lbs of boost.The car was not what I expected since it made 380rwhp before the STS but we both know the boost needs to be turned up to 8-10lbs to see a big increase.
I was busting Zappa's ***** like ussual.Mostly because he had only 4lbs of boost.The car was not what I expected since it made 380rwhp before the STS but we both know the boost needs to be turned up to 8-10lbs to see a big increase.
Zappa, don't feel too bad about the numbers, with 10 more PSI than you I only made 100 more RWHP lol, dynos FTL.
Originally Posted by zapp168
First let me say this...The tuner is a GREAT guy and is THE top notch, and very helpful, if he says the tune is correct then I believe him 101 percent.
**** Don't forget to take this into consideration also. ****
I am just down on myself ...Like I looked up something wrong, or put something wrong in, or in wrong. I hate missing things, or F'in up and being a nuisance to others. I hope no offense, I meant none and took none. I just wanna play on the big boy dyno......
Anyway another Sunday at the shop, Let the EVAP smoker fire for a few minutes and PRESTO leak at the BOV base. I need an O-ring, and this clamp looks kinda bent....One more thing to order and wait for
, no matter it's gonna rain for like a month. 
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Joined: Feb 2007
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From: Seattle area
And Dyno #'s are like how much you can bench press. Just like because you can bench 300 it doesn't automatically mean you can beat up a guy who only benches 200 lbs. Its just a reference to see if your car is benefitting from the mods that you do.
Originally Posted by germeezy1
And Dyno #'s are like how much you can bench press. Just like because you can bench 300 it doesn't automatically mean you can beat up a guy who only benches 200 lbs. Its just a reference to see if your car is benefitting from the mods that you do.
I like that, ok maybe I suck a little less...
Thanks
Originally Posted by Zombie
So what did the graph look like compared to his 380 rwhp pull? 4psi is a pittance though, is that's more like ram air than boost
Zappa, don't feel too bad about the numbers, with 10 more PSI than you I only made 100 more RWHP lol, dynos FTL.
Zappa, don't feel too bad about the numbers, with 10 more PSI than you I only made 100 more RWHP lol, dynos FTL.
4psi is too low.It will be upped and make alot more.Then we can pick up those 98 connecting rods off the floor