So are you saying that because he is making less horsepower at a certain pressure ratio that this is going to change the air flow requirements (lower)? Or am I missing something.

 

Nope, your abolutely correct.
Airflow is directly proportional to HP. You can even log MAF reading on GM to determine the power level, until it pegs it.
In this case with the given hp delivered you can directly look at the airflow comsumed and plot over the map. In this case the less HP derived at 9psi than I originally estimated now moves it closer to the peak eff island.

Phil

 

I would say thats an understatement. It depends on the size of the exhaust coming off the turbo, but a cut out placed pretty close the the exit side will drastically increase spool speed. Thats why you see such huge down pipes on Supras and other imports.

Going to true dual 2.75" on my car brought full boost alot sooner..Ive been told I need to step it up to dual 3"s as Im leaving power on the table.

 

I spoke with the guys here in San Antonio that did your kit.........I was at the Viper/Supra Shootout yesterday in San Antonio, Titan with his Supra, Henessy with a Viper, SW out of Austin and others......Those Supras are on rails. They were lots of 8 second cars...........

How do you like your twin set up from PTK.........

 

I am not interested in doing cut outs. The only real restriction on my car is the stock catalytic converters. The down pipes per side are 2 7/8". It's definetly an exhaust wheel issue. With the large turbine wheel and down pipes it takes a while to build enough exhaust energy to spool the turbo..The compressor wheel can also effect spool because (a larger wheel having more mass in motion), but the majority of it is going to depend on the hot side. I think once the exhaust wheel is matched to the exhaust energy being produced by the motor that it will work great. With a T4 flange the exhaust back pressure will never be an issue within the manfiold. I had asked about switching to a T3 flange and running GT35s....but Jose told me there are still options to down sized the Turbine with a T4 flange...so thats where we are at. Its just R&D..better to get it worked on my car before more of them hit the street.

PTK is also working on a manifold cover to help redirect some heat...I need to vent my hood too.

 

If I were you, before I even consider touching the turbos...Dump the stock cats!!! Putting a test pipe would probably net you 30+rwhp and you turbos would spool like youve never seen. If emissions is an issue get a couple of 3" Dynatech Power cats, they are the same as Random Tech only a lot cheaper ( like 150/each), and they flow ~450cfm. Turbos and cats don't go together.

With all that said.....It is very possible that the turbine side is too large. But I would eliminate the easy options first before I did something else. I can tell you going to larger exhaust brought full boost on approx 400rpm sooner, which is close to what youre looking for.

http://members.aol.com/surfnsun1/dyno1.jpg
http://members.aol.com/surfnsun1/dyno2.jpg

These are links to my dyno sheets...boost was the same or maybe a tad lower on dyno #2...the ONLY change was exhaust. Dyno #1 was with out cats also but on stock L98 exhaust, which is tiny.

 

OMG!! are you serious?

 

It'd be alot easier to just swap out the cats and put it on the dyno to see if it helps before doing housing changes. It helps that your turbo's are right in front/top, as they probably change out in about 30 or less minutes for both of them. Good Luck!

 

Did I say something wrong??

 

no!!! thats a HUGE gain!

i wonder how much ill see when i open electric cuts out especially since i run stock mufflers, no cats

 

Ahhh gotcha. Yea, I had no idea til I saw the dyno sheets how good it would be. Back pressure is basically the enemy of turbos, which explains the huge 4"&5" exhausts you see on the imports. We have duals so 3" is plenty.

You'll need a big wastegates to keep your boost down, but cutouts are gonna be crazy.

 

That not true, effectively you are closing the A/R of the housing and changing wheel that increases backpressure. That backpressure is how you are decreasing the spool time by adding blade area more into the equation. Now, the mass of the heavy T4 style wheels is another issue.

Phil

 

I think that it is true on this system. I would use the TTi Stage III stystem as an example. Look at the back pressure issue on the TTi Stage III with the T25 flange it had. It was a huge restriction on that kit. Phil I know we already had this conversation 1 year ago, I had it with George too right about the time he was clearing material out of the header and fitting it up to a T3 flange. It aided in making a huge improvement to what is now the TTiX system. I always liked the TTi Header except for the flange..it is a very nice cast piece..so don't take the above wrong.

With the T4 flange there should be less an issue. I know what you are saying about the AR. But we changed the AR, a smaller turbine wheel and compressor wheel is going to spool faster than a larger wheels on both. The reason I asked Jose to maybe consider a T3 flange was the availability of T3/T4 Turbos off the shelf..especially a GT35 or 60-1s. I think the only advantage of a T4 vs. a T3 on a 346cid would be at very high boost levels where back pressure becomes more of an issue...don't you? Because this is over email or forum..I will point out that I am not trying to argue with you, just comparing notes in case I have missed something.

The reason being is that I feel if the PTK system had a T3 flange and a pair of GT35s or 60-1s that there would not be an issue of spool up. I think that it is more appropriately matched to the amount of exhaust energy being pushed out of a 346cid motor. However, Jose has explained that there should be some smaller Turbos from PTE that will mate up to a T4 flange. Also with a 224/224 114lsa cam and no back pressure issues..there should be more exhaust pushing out of the motor than with a stock cam...right???

Based on my experience with the TTi Stage III and the PTK, I feel that with the PTK I am on the opposite end of where I was with the TTi Stage III kit..from too small to too big...once we scale it down it should work just fine....I think some of the spool has to do with the full header (long tubes)..while it might be superior in a full drag/indy car setup (vs a log/manifold style headers) where the RPMs are kept high this is probably where it would shine the most at. I just have to trust PTK and Jose to find a set of Turbos that will work best on a 346cid for street/strip..we need to be spooled and making max boost by 3200-3400 to have a good combination. Dalton and Jose told me they would call PTE first thing tomorrow..so I guess I will just have to wait and see what is available. Until that time I am just making conversation.

 

Welcome to the world of enlightenment.

You are learning via the school of hard knocks, and hopefully its a lesson learned. You know I am smiling from ear to ear watching this unfold the way it has.

But, back to the task at hand. Your stuck on the flange bit and its completly missplaced. The flange, weather its t2-t3-t6 really doesnt mean SQUAT. Other than having the "Range" of A/R housing and wheels selection available to use to PROPERLY size turbos. Again and example is the LPE being able to make 750+ with T2 flanges.
If you ever take a turbo apart, you will see that the flange opening is HUGE when compared to the available area to flow the exhaust out of the scroll in the turbine housing. So, the back pressure is generated (Which is good and bad) is from the area around the turbine (A/R) and the open blade area.
Now, I have seen plenty recommendations from arm chair quaterbacks(including you) to run bigger turbo this and bigger that and its not really the case in the real world. Even your so called "superior design" has shown you one of its inhearent drawbacks.

Now, after suffering thru that I will make some simple suggestion.
I would test the compressors to see how they respond at different boost levels WHILE measuring BP at the manifold,I suggest 9,11,13. If you can log EGTs that data is also helpfull.
You can overlay the the data on the compressor map to see if its going to work for you. This will give you 1/2 of the turbo puzzle.
The BP data should be sent to some one COMPETENT to analyze. With those 2 pcs of data you can properly select components to fit within the PTK "System". With the data and proper analysis you should get dam close instead of this part swappin.

Now, My crystal ball would tell me that your going to have to shop somewhere else other than PTE. Other suppliers offer smaller T04 A/R housings (like .50) and different wheels (O-Trim comes to mind) that will spool up a ton quicker than the technology you have tried to date. But, without data your going to continue to guess and prolong the agony.


Phil

 

Show off!

You should have just put One T76 on there and called it a day!

 

Actually I am not learning from hard knocks, it hasn't cost me anything but time..I think that after watching the TTi kit develop from the ARE days to what is available today..about 4 years of R&D that at 8 mos PTK is doing a pretty good job. I come on here to share with people (something I don't have to do) but feel that it is worth it for people's understaning (mine included). Since I have not selected any of the turbo sizes or flanges, I am not really suffering, just getting second opinions. To date my car was down longer with the TTi development and ...well you know. But I did ask for your opinion so I am glad that makes you smile Phil.

My interest in the flange is mainly for off the shelf the Turbo availability. I do think flange size is important...if it is not why would you not see smaller flanges on large displacement large single turbo units that are pushing cars to into the 8 and 7 second 1/4 mile range..so I think the flange size will effect back pressure after a certain boost pressure is achieved.

I would agree that maybe PTE will not have a turbo option and PTK will have to look to Turbonetics or maybe PTE does have something, I don't know, but should by tomorrow.

So far the only real part I have had in this (besides giving updates and supplying the car) is helping with the RAD lay down, plug wires, and Alternator...both which appear to be working...in fact both JPAS and I believe Ryan (NFShotrod) are using the bracket and alt setup from PTK now.

I just enjoy being up front with everybody, whether things have went good or bad..from ATI, TTi, to PTK....so far everything I have been involved in first or at the beginning has been improved upon and is working well. That may not be great for me but it is for the forum...and thats what counts right?

 

lol. Don't rub it in. Had there been an affordable proven single turbo kit on the market a year ago I definitely would have purchased it.

Mark

 

Your missing the point again. The flow rate of the flange is significantly higher than the available A/R and wheel combinations.
You hit restrictions in the turbine section long before the flange opening.

Phil

 

Innovative offers the .50A/R and I believe offer with and with out divided housing.

Full ball bearings are nice too..

Phil

 

No I didn't miss the point, I understand exactly what your saying. The T4 flange is bigger and flows better, but because of the size turbos (off shelf) that I have seen that have T4 flanges (so far) they have been only so small (AR, Trims, etc..). I think there are only a couple of more sizes smaller with the T4 flange, so the next step lower would require a T3 flange to be used with a (off the shelf) T3/T4 hybrid. A .58 AR with a T3/T4 hybrid is going to be a lot different than an .58 AR on a TE63e or PT52. Now the .50 AR that you have mentioned by innovative looks interesting. I was looking at the "split throat" housings..supposedly they group the pulses together better..and work best with 4 cylinders (I have only read), being that I only have 4 cylinders pushing each turbo..it looks like a good choice, the BBs would drop the spool up too..but are very expenisve.

The last change (switched to PT52s from TE63) yielded only about a 300 rpm drop before max boost was achieved....The AR was a .58 with the PT52 (a noticable smaller turbo than the TE63). When the TE63s were on with a .69 AR..switching to a .58 AR (just housings) also dropped the rpms 300 to max spool (from 4300 to 4000 from .69 to .58 ARs). So I think it is going to take a smaller size turbo with a larger AR, rather than a bigger turbo with a smaller AR..thats just my guess. I think if I had a T3 flange, a GT35R with a .81 AR would kick ***.