Just because its degreed doesn't mean its installed correctly.

 

Strip and very little street use, more of a weekend warrior. In order to go to a t-4 I would have to change turbos, I had a t-4 and I am not going back to that. Cam is a possible thing, I am not convinced the cam I have is the optimum cam for my setup. I can re-route the sensing line to the compressor discharge and see what happens. Compression is 155psi with this cam and altitude. It was that new before it fired up and it still is the same. No blowby into the crankcase what so ever. We went with high tention rings instead of the standard low tention rings for better sealing and low oil consumption reasons.

 

Well, if the car isn't going 120 MPH on motor, there is a problem and it isn't the turbo or the turbo system. I would start there. Either there is something wrong with the motor or the transmission/converter. You could be blowing thru a bad converter. I'm sure you'll find it. Sounds like you are competent.

 

It very well could be the convertor. It has 5 years and 40,000+ miles on it with no telling how many 150 shot launches at the track on it. I have not investegated the convertor because I plan on starting my 4L80 conversion after the turn of the year. This convertor only drops about 1500rpm when it shifts now. I am sure I am on borrowed time with it. When I build the 4L80 I want to go to a stall of about 3000 rpm, but the stall speed is not yet set in stone.

I will get back to work on the car after Xmas. I will be on vacation all next week, so I will be in South Texas at the ranch drinking all the Shinner Beer in Humble County, trying to stay sober enough to get that perfect deer . I am making some changes to my charge piping this week, maybe I will have back on the ground before I leave, but I dought it.

 

Here is how we stage my car, your car should be no different. do you have any videos of staging your car?
http://www.youtube.com/watch?v=WsTYX...eature=related


Basically, foot brake the car bring it up to the 2 step, once its on the 2 step you can roll in and stage the car. If you can't hold the car on the foot brake you need to change the car so you can. Move the arm on the brake pedal, add a more agressive pad in the rear, add a 2nd set of calipers.

 

Just something for you to compare. (Sold) 383ci LT1 9:1 c/r ported/polished stock heads, .202/1.57 valves Cam 222/230 @.05 .605 lift, DFI GEN 7+ 6 speed and rear mount turbo. The turbo is a T6 TV85mm with 1.18 A/R the car made full boost 15psi at 4700rpm I have got it up to 20psi by accident. It kinda laggy because of the 6 speed tranny. But I think if I change out the turbine housing with a hybrid like TV75mm turbine .96 a/r with a 85mm compressor. It would perfect for that combo. Unfortunately I did not had a chance to do that and I sold the car. With the 1.18 a/r it start making boost at dead 3700+rpm and hit full at 4700rpm that is with a 6 speed.

PS. Hot/cold pipes are all 3" thru out and swain tech coated and turbine housing is also coated, 5" down pipe. The car was a 93 vette with 3.45 gear ratio.

 

Many rear mount guys have issues if they do this, me included. Boost drops in the high rpms due to pressure drop in the piping/intercooler. It works much better to have the WG reference at the manifold.

 

update, update, update

 

Sorry everyone, I am on vacation, driving to all the family all over Texas. I will not be home to play with the car until Sunday, so I will not have any info until after then.

Merry Christmas every one.!!!

 

What's you're elevation?

 

The elevation is 3919 feet at the local track, Hobbs Raceway.

 

I have this exact same setup but in a truck.... But i Now have a Thumper turbo out back... Everyone has given you Great advice... Timing,camshaft are the biggest things i can see .. also if you cannot give it more then 17% throttle it pushes threw the brakes then your stall must be tight... Also if the car has that Camshaft, That much compression and all that stuff u have listed and cannot run faster then 12.80 on the motor something is wrong....... ALOT of Great advice in this post helping out a fellow rear mount guy also as slow is this is to spool up and make boost as soon as that 50mm gate opens its going to fall flat on its face again.. PM sent

 

subscribed to see this being resolved....good luck.

Chad

 

I worked on it today. This time I capped the inlet to the turbo and the exhaust tips. I am pressure testing all the way threw the engine and out the exhaust. I first pressure tested the cold side to 13psi. Anything more then that an my plug on the turbo inlet blows off. I found no leaks. I noticed this time that the exhast side had no pressure on it. I would have thought that there would be valves overlapped and the air would go to the exhaust side, but id did not. So I pulled one of the O2 sensors out and put a connection in. I then pressure tested the exhaust side and I now know for a fact I am pressuring it up. I found two leaks in the exhaust. The smallest one was were the SLP 'Y' pipe conects to the passenger side cat delete piping. This is a ball type joint and the leak was very small. I repositioned the the piping and re tightened it up and the leak stopped. The other leak was a pretty bad one. It was were the 3" pipe goes into the turbo flange. One side of it is very close to the flange and the guy that welded it up for me welded this part from the inside and missed the gap. So there was a gap about a 1/16" wide and 1/2" long. I removed the pipe and the heat wrap and I welded it up this time. Reinstalled the heat wrap and the piping. I then pressure tested it to 25psi, anything more and one of the two caps on my exhaust tips blows off. At 25psi I could not find anymore leaks. Now the waistgate is dumped to atmostpher and I did not cap it. While I had 25psi on it I placed my hand over the outlet and there is nothing coming out of it. So I know there is no leaks anywere in the sytem at this time.

I took the car out for a drive and I know the lag is less now, not perfect but less. This time it built boost before it shifted into second so it broke the tires loos and I almost shot over the curve and into someones yard. So it is strong under boost to say the least . I did not try to see if the boost will climb past 5 psi. I did not get it over 115kpa. I did have the timing up to 17 degrees with no knock (thanks to the VP113) but the AFR was bottoming out my WB at 9.0. It feels so much better with the extra timing! Scarry actualy.

As for the cam, I spoke with Shawn at Virgina Speed this week and he speced me out a new cam, spring combo. I am presently running Comps beehive springs and I do not trust them under boost, which is why I did not try to see if the boost would go over 5psi. I hope the cam will be here before Friday next week but with the New Year Holiday I am not holding my breath. I am sure the new cam will cure my ills.

So the status is I am waiting for my new cam, springs, and cam lifter tools (I am not doing the Russian Roulette method ever again!). Once I swap the cam and get the pushrod length correct I will start tuning all over again. I will post up my results once I am finished.

Thanks everyone and if you have any more suggestions let me hear them.

 

knew it had to be a leak...its the bane of all turbo cars.

just wait until you get that AFR close and she'll really start to shine

and be careful man...do the testing at the track.

Chad

 

Well no boost leaks is a good thing. Also way too rich can really slow up the spool. You said you are bottoming out 9 to 1?? with VP race fuel 12 to 1 would be no problem. Heck at 5 to 8psi and race you could likely run 12.8 NA ratio .I run around 11.8 on pump 91 no alc/meth. I run around 17 or so max timing with 7.5 psi but I do have 9.5 to one compression. Still now that you are pretty sure no boost leaks lean that car out to 12.0 and see how it does.If the cam and getting afr better don't help enough then would consider putting a small shot of spray on the car.50 to 75 will for sure spool up that snail instantly.

Oh and forget this was long thread but clogged cat if you are running one could cause problems. I have had several turbo cars with clogged cats and buddy had bad one in his sts. That car felt like a 4 banger. It gained like 400 hp I think when we took the cat off!
Cat converters are THE DEVIL! LOL

 

I normaly tune on a load dyno, I was just cruzing it around to see if I did any good, and I would say I am on the right track.

 

Get the tune closer to where it needs to be, AFRs in high 11,s and as for timing, should easily take 17 deg at only 5 psi with race gas and you will have a different animal on your hands.

 

Yes, once I change the cam I will start working the tune out. I just need to get the VE tables right. I have it all correct with no boost, its above 100kpa that I have not started working on yet because I have been working on getting the lag and limited boost fixed first. Once it is all done I plan to be up close to 15psi of boost, around 11.5 AFR and running as much timing as possible, maybe up to 28 degrees with the right fuel and meth injection. Its just a matter of working all the bugs out one at a time.

 

First, I'm glad you found that exhaust leak. That'll definetly kill the spool time. Second, be very carefull beating on the car with the AFR's that rich. You can lift a ring land and eventually break a ring land that way. WITH RACE GAS, you should try to error on the lean side until you get it to where you want it. Again, it's good to see that you are making forward progress.