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Like most things "it depends"

I once had a rear mount turbo car come in and the intercooler was so restrictive a wot run started out at 95kpa and ended up at 70kpa at redline.

So, there was a vacuum in the intake but the turbo was making about 9psi.

Removed the intercooler and it picked up about 150rwhp.

TracyRR

iTrader: (8)

I think i found all of the leaks..... and there were plenty.... Last night i was only able to straighten out the pass injector rail (had to grind the aeromotive rail to clear the intake bolts) so today i aired it up with one injector rail to complete and look for other intake leaks. The drivers side injectors were leaking like no tomorrow....! All injectors were leaking big time. i can't believe they could leak that much from being tilted slightly. *Side note: ever since i installed those aeromotive rails, my garage always smelled like fuel. I could never find a fuel leak so i ended up leaving the garage door open slightly every night so the smell wouldn't be so bad in the morning.* Once i fixed the drivers rail, i had another large leak behind the intake, vaccum line was cut... not the huge hose but the small one. In total, i fixed two broken brackets on the cold side piping that were leaking, all injectors and a vac hose behind the intake. I will blast it tomorrow to find out if that fixed my boost drop...... Fingers crossed...

mike13

iTrader: (27)

If the injectors are leaking that bad at idle I can only imagine what was happening in boost.

TracyRR

iTrader: (8)

I was not able to get heavy into the boost this morning (wasn't able to make it to the "closed course") but it has already made a big difference in spool time which really wasn't a problem before the leaks. Boost comes in much sooner and with much less throttle. The little bit of boost i did see at the motor equals the boost at the turbo almost pound for pound.....so i think i cleared up all my boost drop!!! Thanks to everyone who contributed to the thread!!!!! p.s.... because i don't have all those damn vaccum leaks, drivability is even better now, idle, part throttle, etc.....

87silverbullet

iTrader: (11)

Good deal! I'm glad you got your car running right. Now get that thing to the track and give us some times. Are you near No Problem Raceway? Just asked because I go there often.

TracyRR

iTrader: (8)

hey bullet, hoping to dyno on monday if my tuner is able... I raced in baton rouge for 20 years (when i had a race car) so i'm prob going back there to run it soon. No Problem has a nice track though!!

87silverbullet

iTrader: (11)

Geoff is a good guy. He tuned my 01 ss and it made good power but now i am going bigger so I will be seeing him again soon.

C'mon man bring it down to No Problem, its only a lil further than Baton Rouge Capital. I would like to check the car out.

TracyRR

iTrader: (8)

hey bullet, Geoff is a smart guy.... he is very technical. If i go to No Problem Raceway, I would want to run both tracks..... the road course and the drag strip!!! That would be a good weekend.

87silverbullet

iTrader: (11)

Geoff is a good tuner. He tuned on the car all day to make sure it was just right. My car was previously tuned by another LA tuner but I won't say any names and the car wouldn't find base idle fast enough when coming to a stop and kill with the cam that was in the car. It wasn't small by any means but it wasn't as huge as a magic stick. Geoff played with it until it was right. It idled better and never kills when coming to a stop. To me the tune was band-aided and Geoff cleaned it up.

He tuned a friend of mines camaro with a front mount turbo and just with a conservative tune and 5psi he was making 470 rwhp and there are plans to turn it up even more. Watch the Southern section on here, every now and then they do a track rental and then you can bring the car out and run the strip. There is a guy on here with the screename Junk and he has an 07 z06 that runs bottom 9's and he helps us get the track rentals.

TracyRR

iTrader: (8)

update..... i went to my tuners to dyno today (sorry, no print out's or logs yet).... my tuner can't get the knock (KR) out and it pulls timing on every pull. My best pull on low boost was 640 @ 13.5 pounds (around 5000 rpm) and it had a .9kr.... Most of the pulls were 4 - 9 kr... I was not going to try high boost while having this issue. My tuner geoff tried all that he could think of to clear the knock. The knock was showing up around peak torque (4600 or so rpm's). It seemed the more he pulled timing in that range, the more the computer pulled timing.... One pass had 2 degrees of timing with the same IAT's.... I pulled #7 plug and it had no signs of detonation.... it looked fine. I will have to peak at all of the others but started with the most notorious cylinder. My meth was working well, the IAT were in the 30's C..... i think that works out to around 100 or so F. It was freaking hot today also, 94 degrees. Geoff seems to think that they are false knocks..... Are there any tips to finding out if it is false knocks... p.s... my car ran great, just can't get a clear pass to crank the boost up. Thanks for any advice!! tracy

MY99TAWS6

iTrader: (3)

If its .9 not even 1 then thats nothing. If its 9 then thats quite a bit. One test is to run race gas and see if it still knocks.If it does likely false knock.Have had false on 92 talon that had its pretty common on talons and on my 96z28.In both cases tuned out the knock by literally turning it off. Not the best solution but they would lose a lot of power the turbo talon was the worst.
Its still nice to have knock monitoring especially on an FI car not so important on NA car.

TracyRR

iTrader: (8)

Yes, the .9 was the best pull.... most of them were 4 - 9 degrees. The power really drops off when the timing gets yanked. I will try the race gas trick and kill the knock sensors. The timing is set pretty tame at around 18 degrees at 13 pounds... i plan on dropping a couple more degrees when i crank the boost up. Thanks!

71 chevy

iTrader: (18)

so my hypothesis was correct. fixing all the boost leaks and backpressure issues didnt make any more power.

620whp at 12psi before the fixes
640whp at 13.5 after the fixes

so, my question is this. what type of power would you estimate your engine makes NA. because 14.7/26.7 *620 =341rwhp at 5250rpms,

TracyRR

iTrader: (8)

hey 71, i didn't expect to pick up power at the same boost level. I'm sure in theory it is possible but i was just looking to crank more boost into the motor. I would guess my engine would put out 400ish at the crank with zero boost.

I just read on here that a loud yella terra rocker can set off a knock sensor.... If that is true, that could be my issue because i have two rockers that "clack" pretty good..... Thanks!

Johnv

Try some race gas, but i'm picking if your running a decent amount of meth it won't make much difference.
18 deg @ 13.5 psi is quite abit of timing on a turbo setup, your back pressure may be the culprit causing knock at that level of timing.

TracyRR

iTrader: (8)

hey john, 18 was my ideal timing at 13 pounds, my tuner dropped it down to 15 degrees in that rpm area and it made no difference at all. Yes, i had three nozzles of meth. Thanks!

71 chevy

iTrader: (18)

well, lets do some math here. if your engine is making 400 hp at 5250 rpms NA
with absolutely no losses, 12psi is

14.7+12/14.7 =1.816

400*1.816 is 726 flwheel hp. lose 15% for drive train losses and you have
617hp at 12psi

or
652hp at 13.5 psi ideal

so, the only way im seeing to get to your 800rwhp goal is to up the boost, or raise the NA hp by raising rpms(cam issue?)

mike13

iTrader: (27)

I would check those rockers like you mentioned, dropping timing should change the amount of kr. I think if you can chase down the kr issue turn more rpm your horsepower will be right in the ballpark.

TracyRR

iTrader: (8)

hey 71, Looks like i'm real close using your math. Yes, my plan is to raise boost to 18 - 20 pounds to hit my goal of 800rwhp. Assuming everything works as it should (big assumption with all of the bugs that i've had!), i should be right at my goal. I wonder if a larger cam in my setup would make a significant increase (60rwhp) or a minor increase (20rwhp) in power?.... just curious.... Thanks!

TracyRR

iTrader: (8)

hey mike, looks like i didn't have enough preload on the lifters....between a 1/4 and a 1/2 turn. I found a couple really noisy rockers (heavy clack) so i temporarily removed the shim under the yella terra mount and remounted the shaft and the noise is much better. I ordered some .025 longer pushrods (7.425") so that should give me enough preload to decrease the rocker noise and of course i will reinstall the shim under the mount.... The valve stem tip swipe was better with the shim under the mount.
I also found out why my 6.5 wastegate springs were giving me 13.5 pounds of boost with the boost controller all of the way to zero..... i had a bad leak in the boost controller line so it was basically venting the wastegates to double the estimated spring pressure. My boost controller should now be able to control the boost. I am learning a ton ironing out all of these bugs!! Thanks guys for the help!!