Vadian

iTrader: (2)

UPDATED Post #53

Here are some early results. Car is being tuned (with EFI Live) by Eric Brooks from the Ford world. Awesome and extremely talented guy!

I did not include the AFR graph because it is still being finely smoothed out. However, I will say that AFR is around 11.1
I created this post primarily for some insight on a technical concern; thus the boost graph

-440ci LS7/L92

-Turbos are T4 T61s/ Ebay/ China special. I know these are way too small for the motor and will be replacing them shortly.

(Contrary to everyone's speculation, these turbos have been very good. I've had them on for about 8 months and about 1000miles; zero problems, zero shaft play)

-Wastegates are 38mm and springs are .5bar (~7.2psi). Referenced directly from the compressor housing so pressure loss through the intercooler is not accounted for. The pressure sensor for the dyno is seeing intake manifold pressure.

- Exhaust is full 3" except for a small section (less than 1ft) of 2.75 pipe which will be getting replaced with 3" No cats, no mufflers.

So, my concern is that the motor makes just shy of 9psi on this run (I know, wastegates are not keeping up), however, it tapers off to about 6.26psi at the end of the run. I believe this to be the cause of the turbos running out of steam but someone else mentioned it could be too much backpressure. Or perhaps it is a combination of both; one being a result of the other.

What do you guys think?

67Firebird455

iTrader: (27)

Twin 61's are too small for that engine, that's why it's dropping off. You have a bit of creep because the WG is too damn small for that big of an engine at such low PSI.

67Firebird455

iTrader: (27)

BTW - What do the compressor maps look like on those "T61's"? Like the "Super T-70" isn't a 70mm turbo at all, and makes like 500bhp, not 800. As for turbos, if you're on a budget, twin MP T-70's will work awesome, or a set of airwerks budget units for $600 a pop.

Camaro_Zach

iTrader: (19)

lol thats awesome. I love seeing results of the ebay kits that are good. **** 700 rwhp for the $$ you paid and with those crap *** turbos is just freakin awesome.

Also, I once bought this $10k kit from a well known turbo kit manuf. and well, the AMAZING BOV's they gave me leaked under boost, so I couldnt build any kind of power and the car made like 600 rwhp and never hit the gates. Put in new bov's and the car made 20 lbs of boost before I **** myself and got my foot outta the throttle. Point is, yay ebay.

navymitch12

iTrader: (1)

engine bay pics! haha

nice power for undersized turbos and 9psi

Vadian

iTrader: (2)

I knew these were the problems. Guess I'll just have to increase the boost with some new, larger turbos to take care of the creep.

I just needed some reinforcing opinions from others, thats all.

Yeah, it took a lot of work but now its worth it. I've got about 3k into the kit. Not bad at all.

I'm definitely gonna have to look at the BOV now that you mention it. I got it from the same guy who sold the kit; basic Tial knock off.

Thanks!

One added.

Camaro_Zach

iTrader: (19)

I never understood how the PTK kit did well...how do you change your plugs? How do you change your belt? How you do anything honestly? WOW that engine bay is INTENSE! I know tons of people have this kit, and they all make huge power with the right sized turbos but damn! More pics so I can marvel at the complexity of that kit!

Vadian

iTrader: (2)

You can get to the plugs on cylinders 5 thru 8 from the top no problem. I get 1 thru 4 from the bottom by removing a short section of exhaust. Its more work, but really isn't bad. You can also take off the turbos and manifolds in about the same amount of time.

As for the belt, 5 min job. Remove the turbo inlet pipes and the throttle body pipe.

It really isn't as bad as it looks. I can have the whole kit off in an hour. The longest part would be removing the front bumper so I can take the intercooler out.

engineermike

Doesn't the 1000+ rwhp, 158 mph IPS vette have GT35R turbos, which are also 61 mm?

Louis

iTrader: (7)

Correct, and the LG 210 standing mile vette, which made over 1000 as well.

61s are not too small, there is another issue, unless the "61s" are not really 61s.

Vadian

iTrader: (2)

They probably aren't. I never did take the time to measure. That, or they are are just really inefficient. Though my IATs never got above 111*F

I'm definitely replacing them either way. Just gotta decide what.

67Firebird455

iTrader: (27)

That's why I said "T61" lol cuz I bought a chinese turbo years ago to mock up, and realized it wasn't even close to the same dimensions as the real turbo.

engineermike

The temps after the intercooler say more about how efficient the intercooler is than the turbo.

Vadian

iTrader: (2)

Yeah, that's true. Totally slipped my mind.

prostkr

Mike,

You seem to have a point to make, do you have time to elaborate? His IATs never went above 115 degrees with no fans on the ATA. I'm new to the turbo world and Ill listen/learn where and when I can. (I was lucky enuff for Vadian to let me help him put this car together) Thanks for the input! Jon

extremetoy

iTrader: (17)

if you reference the wastegates at the manifold rather than right off the turbos the boost would probably be more consistent.

engineermike

My point are:
a) if they are truly 61 mm turbo's, then they should be enough for 1000++ hp.
b) if you know the boost level, ambient temp, and compressor discharge temp, then the compressor efficiency can easily calculated.

Vadian

iTrader: (2)

Measuring the temp after the intercooler tells nothing about how efficient the turbo is at those conditions at that time. It really tells nothing about how efficient my intercooler is also, unless, I have a temp sensor before the intercooler as well. The difference in the two temperature measurements will give you your efficiency percentage for the IC.

navymitch12

iTrader: (1)

i dont know why but for some reason i thought you had an f-body..good power numbers but something is lacking for sure. I have a c5r 427 with 64's and the PTK version of the PTK kit.



The belt can be changed from the bottom, and plugs can be changed in 45-60min. And it looks GREAT!!!!!!!!!!!!!!

Camaro_Zach

iTrader: (19)

Thanks for all the info. I guess that makes sense, since its all out there in the open and not all hidden, its easy to tear apart, as opposed to many other tuck away kits.

Interesting.