1320

iTrader: (6)

I tried to read it all, then I was remembering someone getting mad at me in another thread for something.

Did I miss the part....
1. that you check the waistgate spring pressure?
2. Check the installed and open hieght of the waist gate spring/ valve?
3. get accurate pressure numbers from pre turbo exhuast?
4. Temperature check the turbo housing, idle, after cruise, post power braking?
5. In another thread you commented that you cant get a tangential housing? and thats why you cant run a valve? Either you dont understand the valve or what tangential is cause they are unrelated. You could run an oncenter housing with a valve, just fine. It just needs to be a divided housing.
6. Why or rather how is only an oncenter housings available? Seems strange since they do not flow as well as a tangential housing. They were designed for fitment issues.
7. When I leak check a system, I dont use my calibrated hand, mine simply isnt that good. I use a leak down gauge and get hard numbers.


I wouldnt have built it this way at all. I would have used a th400 or 4l80(same thing for this argument) from the go. I wouldnt have even tried to run a 88 with out every possibly thing done to make it right.
I would have
1. run th400
2. started with 3500 isg stall
3. coated the manifolds
4. coated and wrapped the entire exhuast
5. ran 3 nch everywhere
6. quick spool valve
7. coated and blanketed the exhuast housing
8. divided 96 to 1.1 housing
9. 3.25 gears or higher (lower numerically)
10. tall tire....28 +
11. two step with retard
12. trans brake
13. larger exhuast post turbo then outlet

Of all the waist gate springs I ve tested, the one common theme is none of them are what they are suppose to be. I have box of them, and when I need one, I measure the current, then measure each one in the box, and choose.

Texas_WS6

iTrader: (9)

I am not sure what to think about the whole spring issue. If I was referencing the boost pressure at the compressor outlet, and I had this big of a difference I would be concerned there must be a huge delta p in the piping. Seeing as how i am referencing the gate at the manifold I am not really worried about the discrepency as long as I am not making 22 psi or grater at the compressor in order to get 12 at the manifold. I think I will move my boost gauge to the compressor and see what the delta p is.

I had come to the conclusion the convertor was the problem. Looking at the data logs, it looked as if the convertor was too tight, I could only hold the car to 2500rpm and it would only flash to about 3100 rpm. Thats why I had it loosened up. Comparing the logs the boost looks worst, and the time slips show no improvement. Starting in second gear (today, and I did not make a complete run) I was able to hold the car up to 4000 rpm and the turbo spooled up quicker.

As for the trans, I agree, thats why I have two 4L80's on my bench. I think a level 4 4L80 with a brake will out live a level 7 4L60 with a brake. I was toying with the idea of the 4L60 only because it would be about 2000 dollars cheaper and it has a better first gear, giving me the ability to run 2.? rear end gears for top end. But now that i have had the convertor played with, I realy do not like that much stall, I would now need to replace it if I stayed 4L60, so 1000 dollar diference is not enough to make me stay with the 4l60.

Texas_WS6

iTrader: (9)

I like the way you listed, it makes answering much easier.
1. I did check the springs with the color coded chart from Turbo smart. I did check the 10 psi spring while installed with a calibration tool and noted the cracking and full open pressure of that spring. I did not write it down and it has been several months, so what I pressures I remember might not be correct. I will bring the tool home from work this week and record and post them.
2.No, I do not know the valve travel. I did not messure the spring height, and I have not messured the chamber distance.
3. I can bring home some transducers to test this. I should be able to record this with HP Tuner. I was going to do this but I saw no need once I determined the valve was infact opening and limiting the boost to 5.5 psi with the 10 # spring.
4.I can shoot the housing with my Raytec and post temps up.
5.I called Forced induction and asked for a divided housing so I can run the valve. They told me there is no divided housing for my turbo.
6.I think I do not understand tangent and on center housings. I thought tangent was the divided housing. I am not sure if mine is tangent or oncenter.
7.When I last tested it before today, I plugged the turbo inlet and the exhaust outlet. I removed the O2 sensor and installed a pressure regulator with a compression gauge hose with the shrader valve removed. I then pressurized the system to 12 psi, any more and the plugs would blow off.I then used Snoop to look for any leaks. All that were found were repaired. I checked again after the repairs.

Texas_WS6

iTrader: (9)

This is my first turbo build, and I am learning the expensive way. I do plan to work this out, what ever it takes.
1. I really want to keep the overdrive and lock up. Isn't the 4L80 a 400 with over drive?
2. Sounds good.
3. This is something I could get done. What material?
4. The exhaust is wrapped, but not coated. Same coating as with the manifolds?
5. This is not out of the question.
6. I would like to do this, but I was told by Forced Inductions this is not possible.
7. Good idea.
9. I agree.
10. Got it.
11. Ordering one.
12. Doing this.
13. Can you explain why?

Texas_WS6

iTrader: (9)

I hope it was not me.

Thanks for your help.

CarsandWomen

iTrader: (19)

texas ws6, you missed number 8 lol. mad props to you for sticking with it, id have burned it to the ground by now.

stevegrizzle

could the wastegate be stuck open?

Texas_WS6

iTrader: (9)

Na, I do agree with the ar sizing, I am using a .96, a 1.1 with a divided housing and a valve would be sweet. I just don't know wich size I would go with if I had a divided housing.

I know what you mean. My buds car is a 98 Camaro with a 6.0L, forged rods and pistons, low compression, stock 6.0 heads and a EPP blower cam. I spent over 12 grand to build my 408, he spent around 6, plus a D1SC set for 14#'s and the damn thing flies!!! He and I do the tuning to both cars, and his build has been really easy. He cuts 1.49 60fts and runs 10.60's at 128mph. My build has been very expensive and very troublesome, and it has not preformed as expected NA or Boosted. I have 20 grand in the whole build now and I am very frustrated with the results. I have so much in it now I can not turn back.

With everyones help here, help from the sponsors, and a few more $bones$, I am possitive I will either get this thing right, and it should be killer. There is no reason it should not run 9" when I am done and catch some sweet air off the line.

Call me crazy, I refuse to cage the car, it is street legal, I do take it out on the street from time to time, it still has the A/C, cruise control, everything, I put a killer stereo in it last summer. I bought this car new in July of 02 in Batton Rouge LA. It has survived one huricane and my divorce, I plan on being buried in the damn thing! LOL! It still looks completely stock, no tinted windows, stock stance, all stock interior except for the 3 gauge cluster on the drivers post. If I could get the exhaust note to sound stock I would.

I do not realy plan to race the car. Nor do I plan on driving it much. I will take it to the track on test and tune days (when our track is lax on the rules) and give it a few runs. I will take it out on the town to cruise (I do not street race) and intimidate the local street rods from time to time (they are already impressed with it). Mostly I will trailer it to cruizes like the Sumers Last Blast in Vernon Texas, and drink alot of Shiner beer while working on it in the garage. This is not my mid life crisses, I have always had hot rods, but I have finaly gotten to a place in life to be able to build something crazy like this. I am going to get a new Plumb Crazy Purple Challenger for my mid life crisses fix .

I do need to get this car finished soon. I have 3 Toyota FJ40's (one 1968, one 1972, and one 1974 models) to get running, one for each of my sons, and I need to get started on my 1970 Plymouth GTX (it will take allot of work!). Not to mention the wifes list of house projects .

Texas_WS6

iTrader: (9)

I do not think it is. The valve seat and the valve face are both in perfect shape (it is a new valve), and because it is dumped to atmosphere I can see the valve is seated and when I pressure test the system I can verify it is closed and sealing good.

Texas_WS6

iTrader: (9)

Let me better describe my turbo. I posted it as a PT-88, it is not a Precision Turbo. What it is exactly is a GT-88 with a Precision Turbo .96 AR T-4 Turbine housing on it. I bought this turbo from Beast (member here) and sold my new PT-76GTS because every one here and the guys at Forced Induction told me it was too small for the 408 and a GT-88 would be perfect. Beast never installed the turbo on his build because of the limited space he had. So the turbo came to me new and in perfect condition. It had a 1.08 AR T-6 Housing on it which is the smallest housing Garret made for it. From what I understand, Garret changed there nomiclature and now makes an upgraded version of this turbo. It is now called a GT-4788, but the turbine wheel on a 4788 is a little different and the center section is different. The GT-88 has a 3rd generation turbine wheel but they both use the GT-47 compressor wheel and housing. This info I gathered from talking to Forced induction. When looking for a smaller AR turbine housing, Forced Induction help me by letting me know that the Turbine housing Precision makes for the PT-88 series would fit the GT-88, and they gave me the correct part number. So I contacted Precision turbo and told them what I was doing and ordered the housing, and it fit correctly. The guys at Precision told me their PT-88 (or PT-4788) and my GT-88 used the same 47 compressor wheel and compressor housing, the same turbine wheel but the PT used their housing and once I put thier housing on my Gt-88 it would be the same turbo configuration as theirs. Does all that make sense? Thats why I called it a PT-88.

Now with that said, talking to Forced Induction, Garret does not make a divided housing for the GT-88, but we did not discuse if Precision made one that would fit my turbo. I am assuming any of the PT-88 housing will fit my turbo so maybe I need to contact Precision again to find out. Bad thing here is I spent $500 bucks for the housing, v-band clamp, t-4 weld on flange, and shipping. But if they make one that will work with this turbo, I will bite the bullet and get it. So if anyone has any info on this please say so.

Texas_WS6

iTrader: (9)

Sorry for being long winded here. I just want to make sure I am giving as much data as possible.

Texas_WS6

iTrader: (9)

I still have the 1.08 housing. I am holding on to it incase I give up on the rear mount idea and decide to move the turbo up front. Heck I still have everything I ever took off this car put up. Every thing, engine, Mosoon stereo, speakers, amps, exhaust, convertor, I mean all of it, just incase I decides to go back original some day.

slow67

iTrader: (2)

1. Yes, a 4L80 is basically a Th400 with overdrive and electronic control. Shares MANY parts. Only downfall is stock input shaft tends to break around 750hp (stock th400 lasts till around 1000hp).

SMG

iTrader: (1)

i personally think you might be feeding the turbine inlet with to LARGE of a pipe.... you might be slowing velocity down to much. Now i understand the example that im about to give is completely different but... We have built (so far 2) remounted twincharged cobalt ss/sc cars with the turbo hung out back like an sts kit feeding the blower, we have found the best luck with the stock 2.5 exhaust stepped down after the axle to smaller than 2.5 to feed the turbine. Now obviously its retains the blower which helps with spool, but we have run the cars with the blower bypass open (eaton m62 blower) and had full spool by 3,800 with a gt35r on a 2.0L ecotec....Sorry for going into detail about a totally different setup but, try feeding the turbine with a 2.5 pipe and see what happens

Texas_WS6

iTrader: (9)

I see what you are saying. With the larger diameter piping you slow the velocity down, giving the gasses more time to cool, going to a smaller diameter pipe will help keep the velocity up so the gasses have less time in the pipe before the turbo, less time less heat loss. I can see how reducing the pipe diameter even more farther down the pipe could help keep the gasses velocity up too.

Food for thought here.

Texas_WS6

iTrader: (9)

I am going to order the 4L80 either later this week or early next week. I spoke with the builder and he is going to put a 300mm billet input shaft, billet drum, and lots of other stuff, plus the brake in it. i will then get with Circle D and order a billet double (or triple what ever they say) convertor with around 3400 stall. I am going to call Precision here in a little bit and see if they have a divided housing for my GT-88. If they do I am thinking I should go with one larger then .96 ar. If they don't then I guess I am stuck with one of the two I already have.

Once the trans is in, I will add each thing until I get this the way I want it.

Zombie

iTrader: (2)

Ever think of selling your existing turbo and swapping to a BW 80mm (I think they also have an 82mm comp now as well)? Bit on the small side for a 408, but a lot more turbine housing/wheel options. Could probably make 800 rwhp at 15psi (I think I'm pretty close on a 370 with stock heads) and be made to spool wickedly fast. My setup is waaaay fun to drive.

I know my same turbo will spool quick on a 408 even without the valve, I'm guessing the valve reduces lag on my setup by 50% now that it opens and closes the entire way and could be made to spool even faster by holding it shut until a given boost is reached.

Texas_WS6

iTrader: (9)

I wish I still had the 76. I would consider selling it if all else fails.

Texas_WS6

iTrader: (9)

I did call Precision today and checked to see if they had a divided housing. They do not. When ordering the .96 turbine housing from them, Patrick said to me puting that housing on my GT-88 would make it the same thing as their PT-8847. I never heard of or saw a listing for their PT-8847 so I figured I heard him wrong or something and he ment PT-88. I down loaded their price sheet and right there under the PT-88 is their PT-8847. So I guess this thing is more like their PT-8847. Maybe someone who knows PT turbos can clear this up for me. My GT-88 turbo according to Forced Induction has a GT-47 compressor wheel and housing, the frame is not a GT-47 frame, and the Turbine wheel is a 3rd generation wheel. Does anyone know what compressor wheel/housing and what turbine wheel is on the PT-88 and the PT-8847? I dought knowing this will make a difference on what to do to make it spool faster, but I would like to clear this up for my own benifit.

OUTLAWZ RACING

iTrader: (9)

Well maybe we can work somthing out as far as the turbo I have a gts 76 on my car now, but im going frontmount this time around. But I would change the rear gear big time , I just noticed it. My buddy went from 3.73 in his stalled auto rearmount to 3.42 and said it spooled instant and his tune is garbage describe by him lol. I would even go 3.23 in your set up it will def help spool.

Pm me about the turbo if u want.