T76GTS or T88? What do you guys think?

[86merc]

OK After years of lurking on the boards I am looking to have a custom kit made for my car. The kit will be made by forum members Shaun and Anthony (of quad turbo Fury fame). I originally was thinking of a T76GTS. But reading into it more I am not sure that is the way to go. Mainly due to the fact that the t4 flange and down pipe sizing. I don't want the huge restriction if it will hurt my combo. The t6 frame T88 looks like a good option. But I am not sure if the spool time will be slow for the street. And fitting the T88 and piping may be a chore in my cramped engine compartment. I have all accessories working on the car and removing them (minus smog) are not an option. So what do you guys think? Will the low stall speed converter and t88 make a slow spooling combo? Will the t76 limit the power the car will make? Will the t4 housing kill the power potential?

I would like the car to run 9's all day long. On pump gas (with spraying meth) would be nice. And maybe some race gas to try and run 8's??? haha This years goal was to run 10's on the radials and I blew that way with 9.8's. lol So I will not lie and say I only want a 9 second car and never want more. It is addicting as we all know. But I would rater sacrifice a little ET & MPH to have a car that I will have no issues with on the street.

Here is a quick run down of what I have. If you need more info please ask.

86 Capri that weighs 3550 with the Vortech and me in it. I will be adding a 10pt cage and a few other safety items. So I expect that weight to be 100-150# more when all done.
331 ci Forged Dart IE block with 8.6 to 1 compression with my heads
AFR185's (58cc combustion chambers, no exhaust upgrade)
Holley systemax II intake
70mm t/b
cam 232/242 @ .050 .544/.560 114 (this will most likely change. I have to look into that as well.)
83# injectors with a fuel system to support plenty of power
AEM EMS for tuning
AOD built (I will be adding a trans break over the winter)
PI converter (This is mainly a street car so a lower than optimal stall speed will be used. Around 3500rpm. Any higher and my trans guy and Lentech say heat will be a issue.)
9" Ford rear end with undecided gear due to undecided tire combo. Most likely a 275/60/15 drag radial will be used.

[Forgery]

At a 331 displacement I'd say T76GTS

[Drlee50]

the need for speed is sick!  I have it too LOL.  I am selling my twin kit and going single.  you have seen it in action at byron i am sure--
http://www.theturboforums.com/smf/index.php?topic=100110.0

i am going to an 88mm myself and i am shooting for solid 8's  all day long.   my car runs mid to low 9's without a sweat at 148-155 mph.   the way your car hooks, this kit would probably put you in the high 8's at 20 psi.

[Gen1SVE]

Here is a clip of my 306 8:1 compression, with a t-6 88mm with 1.32A/R exhaust housing @ 13psi, I do not have all the acessories.  Spool does suffer a little but a 331 with 8.6:1 would be better.

http://videos.streetfire.net/video/a580c61e-a092-45c8-a50b-99e300dc61ea.htm

[4Jenna]

Good thread I had almost the same question!

[86merc]

the need for speed is sick!  I have it too LOL.  I am selling my twin kit and going single.  you have seen it in action at byron i am sure--
http://www.theturboforums.com/smf/index.php?topic=100110.0

i am going to an 88mm myself and i am shooting for solid 8's  all day long.   my car runs mid to low 9's without a sweat at 148-155 mph.   the way your car hooks, this kit would probably put you in the high 8's at 20 psi.

Hey Lee! I saw you were selling the kit. Good luck with the sale. Would be nice to see the car go 8's. Even if you keep the kit you should be good to go with full boost. Work on the suspension and tuning to leave soft and applying the power and you should be good to go. Maybe get Bob to keep helping at the track. Works for me. haha

And my car hooks because it leaves so easy. No trans break and a 2500 stall it doesn't put any power to the tires to cause them to spin. hahaha On my 9.8 pass the data log showed it took .85 seconds to make 10# of boost, 1.30 seconds to make 15# and 2.21 seconds to make 20# right before I shifted into second. I imagine a T88 would be better even if I didn't load it much. lol I hope I can still get the car to hook with 10# or more on the trans break.

If I didn't want to keep the A/C and P/S I would consider your kit. But I told myself when I bought the car I would not pull it off. I gutted my last car and hated driving it after that. But I did tell a few people about your kit. Hopefully sooner or later some one will bite on it. Good luck with the sale. 

Here is a clip of my 306 8:1 compression, with a t-6 88mm with 1.32A/R exhaust housing @ 13psi, I do not have all the accessories.  Spool does suffer a little but a 331 with 8.6:1 would be better.

http://videos.streetfire.net/video/a580c61e-a092-45c8-a50b-99e300dc61ea.htm

Hard to tell as you can't see a boost gauge. And the fact that you had to pedal the car says there is more power than you can use anyways. lol How does it spool from a roll? Does it take a noticeable amount of time or is it pretty quick? Thanks for the help.

Also, Shaun has a t6 turbo we will try and fit in the engine bay tomorrow. Hopefully there is room there. A front low mount was another option as I have a lot of room with the RS nose on the car.

Keep the suggestions coming guys! 

[Drlee50]

its tough to fit  a big turbo like that and keep the accessories.  I am sure it can be done though. for 9's if I was you Id go with a 76mm.  its  smaller and you will need that for sure.  you planning on an intercooler?

[engineermike]

The T76GTS will easily support 9's and a few folks have gotten them in the 8's.  If you're looking for something better in a mid-frame (GT42 size), then check out the ST80.  It's a T4 turbo, but will support more power than the PT88 (1300+).

[FastDriver]

Running 8s would be just about the limit, or possibly even exceed the limit of the 76GTS' capabilities at your weight.  You could certainly run 8s with the 88mm, and it would spool slowly as you suspect; I'd guess 4000rpm to full spool.  Have you considered something in between?  The GT42R-76 from PT would spool almost as quickly as the 76GTS (same compressor wheel), but it's rated at 100 extra HP and has put quite a few cars into the 8s.  Another possibility would be a turbo that I've heard about...  I think someone is putting an 80mm wheel in a GT42 housing.  Just a couple of ideas to run by you.

How high do you plan to spin your engine?

Chris

[86merc]

its tough to fit  a big turbo like that and keep the accessories.  I am sure it can be done though. for 9's if I was you Id go with a 76mm.  its  smaller and you will need that for sure.  you planning on an intercooler?

I am still in the planning stages. But I think a air/air will be what we use. A air/water intercooler would be a better option. But the extra plumbing and such is a draw back for sure. I have seen a couple using a smaller air/water intercooler. But no real feedback or comparisons on them. Unless I find some good info about the small air/water intercoolers I think a air/air will win out. The car will be driven on the street with 10-15# I bet. I can't see a air/water being that much more efficient as a heat exchanger when hot versus using cold water and ice at the track. And I have a Snow Meth kit I will continue to use. That will help as well.

The T76GTS will easily support 9's and a few folks have gotten them in the 8's.  If you're looking for something better in a mid-frame (GT42 size), then check out the ST80.  It's a T4 turbo, but will support more power than the PT88 (1300+).

I know a lot of them show the compressors can make good power. But I am more worried about the exhaust side. Yes the compressor side may be able to support 1300hp, but I doubt the t4 flange and smaller sized down pipe will let most motors make that kind of power. I know my 1 5/8 shorty headers and 2.5" exhaust came loose after every blast at the track. I don't want the exhaust to be so restrictive and have a back pressure ratio of 3 to 1 or more. I am by no means a expert. but just going by what I was told by a few more knowledgeable people and what I have read on here. So I am still learning. That is why I am asking questions and taking it all in. Thanks for the help guys.

[86merc]

Running 8s would be just about the limit, or possibly even exceed the limit of the 76GTS' capabilities at your weight.  You could certainly run 8s with the 88mm, and it would spool slowly as you suspect; I'd guess 4000rpm to full spool.  Have you considered something in between?  The GT42R-76 from PT would spool almost as quickly as the 76GTS (same compressor wheel), but it's rated at 100 extra HP and has put quite a few cars into the 8s.  Another possibility would be a turbo that I've heard about...  I think someone is putting an 80mm wheel in a GT42 housing.  Just a couple of ideas to run by you.

How high do you plan to spin your engine?

Chris

A different sized turbo or even a hybrid turbo is a option. I mainly threw those specific turbos as the are common and priced pretty cheap. I am on a tight budget and a $2500 turbo would blow the budget. So I am open to a suggestion on the turbo and whole kit for that matter.

If a t88 would have full spool by 4000 that would not be bad. At least I don't think so. If I have a 3500 stall it would make good boost at that speed. And from a roll I can imagine it would be above 4000 rpm anyways. And if not it would be pretty quickly.

I would like to keep the engine rpm under 6600. I have taken it to 7200 with the current combo because of tire size and the gear I have. I really do not want to continue to do that. 

[86merc]

Well Shaun came over and with his 4th dimensional thinking it looks like we have a game plan for the t6. Working around all the accessories will make it a harder build for sure. But if it there is a will there is a way. Right?  It looks like there is even room for 15"-18" of 5" pipe exiting the exhaust housing. Then hopefully to a Y and dual 3.5" all the way over the axle. The front end does not offer a lot of room for a big intercooler. We have to pull the front end off the car to see what we actually have to work with. A air to water may have to be used due to space limitations. So I am excited that if we decide on a t6 there will be a way to make it work.

Now I need to figure out what turbo to use. From what I read so far the S400 line looks like it could be another one to look into. That may be a option too. hmmmm option, options, options. 

[86merc]

oops.

[Drlee50]

where u gonna put it??

[Hemann]

Where you putting a 5 inch exhaust and get it to the back?

[SomewhatStock]

Come on guys step up to the Garrett GT series turbos...Lee if you want to run a single 88, get a GT-47...Have you seen my most recent video?   Its turned as far down as I can get it   If thats too much, grab a GT42 and go 8.80s all day.

[engineermike]

I may be preaching to the choir, Will, but the 76GTS has the Garrett GT42 turbine wheel in it and maybe even compressor too.

[SomewhatStock]

Much different cover and eventhough the wheel may be the same, GT42s have been faster.

[Drlee50]

Come on guys step up to the Garrett GT series turbos...Lee if you want to run a single 88, get a GT-47...Have you seen my most recent video?   Its turned as far down as I can get it   If thats too much, grab a GT42 and go 8.80s all day.

 i have already decided on that one lol--

 do you think  it is realistic to have full boost by 5500 with that turbo and 336 ci ?  3600 stall-- currently pulls thru to 4000 in 1-2 seconds for 10 psi  boost on the t-brake.
here is my flow map:

http://www.squirrelpf.com/turbocalc/index.php?version=4&target_peak_power=1400&engine_disp=336&engine_disp_factor=1&target_af=11.3&bfsc=0.43&max_ic_loss=1.7&rpm_redline=7200&rpm_peak_power=6500&rpm_max_boost=5500&rpm_min_boost=4000&vol_1=89&vol_2=93&vol_3=90&vol_4=87&vol_1=89&vol_2=93&vol_3=90&vol_4=87&intake_temp_1=90&intake_temp_2=120&intake_temp_3=130&intake_temp_4=135&turbo_n=1&map_sel0=123&map_sel1=53

[SomewhatStock]

I have no idea where it makes full boost, but mine makes 20lbs on the TB at 4000 rpm and with the knob all the way out, it makes 24 out back. 

[86merc]

where u gonna put it??

Well it looks like the best place is on the passenger side front over the frame rail. It will have the down pipe pointing across the front of the motor. The air inlet will point into the inner fender well. If not actually in it. If we keep the Vortech brackets we gain a lot of room with the alternator down at the bottom of the motor. That makes extra room up top for the turbo. I already have a double pass radiator in the car. So the water inlet to the radiator is on the drivers side. That also gives us extra space to work with. Also helpful with the down pipe being no where near the radiator hose.

Where you putting a 5 inch exhaust and get it to the back?

With the turbo mounted up high as possible, the slim Flex-A-Lite fan I use and a few other tweaks it looks like we could have a 15-18" run of 5" pipe. Then merge it into two 3.5" pipes that will turn down just in front of the air compressor and power steering pump. Then they will go under the motor some where through the aftermarket k-member. Then hopefully we can run the 3.5" all the way back over the axle. If we need to we can gain some more clearance by cutting the radiator support and moving the radiator forward some. 

[Drlee50]

Well it looks like the best place is on the passenger side front over the frame rail. It will have the down pipe pointing across the front of the motor. The air inlet will point into the inner fender well. If not actually in it. If we keep the Vortech brackets we gain a lot of room with the alternator down at the bottom of the motor. That makes extra room up top for the turbo. I already have a double pass radiator in the car. So the water inlet to the radiator is on the drivers side. That also gives us extra space to work with. Also helpful with the down pipe being no where near the radiator hose.
With the turbo mounted up high as possible, the slim Flex-A-Lite fan I use and a few other tweaks it looks like we could have a 15-18" run of 5" pipe. Then merge it into two 3.5" pipes that will turn down just in front of the air compressor and power steering pump. Then they will go under the motor some where through the aftermarket k-member. Then hopefully we can run the 3.5" all the way back over the axle. If we need to we can gain some more clearance by cutting the radiator support and moving the radiator forward some. 

its always good to try to keep the front weight on the drivers side if possible. with your accessories, it may not matter much in the end.   take alot of pics of your build!

Good luck with it!
Lee

[86merc]

Much different cover and eventhough the wheel may be the same, GT42s have been faster.

I think I read that you said you were only able to run 8.8's in you car. I am sure I have a few 100# over you. So I am sure the gt42 or t76gts may not be able to power me into the 8's. But that is the least of the build goals.

its always good to try to keep the front weight on the drivers side if possible. with your accessories, it may not matter much in the end.   take alot of pics of your build!

Good luck with it!
Lee

Yes the weight on the passenger side is not the best. But unless I cut out the passenger inner fender and added a bulge to the fender I don't see it going on the drivers side. lol If we went with a low mount it was going on the drivers side. But there is not room for it there really. The current plan is the best one I think. I am sure when all done the 3800# weight and ridiculous weight ratio will be something to over come. But this is not a race car build. So I have many limitations. So we will work around things best we can. We will see what happens.

There will be plenty of pics on the build up. I am sure Shaun, Anthony or I will start a build thread.   

[Gen1SVE]

Here is a clip of my 306 8:1 compression, with a t-6 88mm with 1.32A/R exhaust housing @ 13psi, I do not have all the accessories.  Spool does suffer a little but a 331 with 8.6:1 would be better.

http://videos.streetfire.net/video/a580c61e-a092-45c8-a50b-99e300dc61ea.htm


Hard to tell as you can't see a boost gauge. And the fact that you had to pedal the car says there is more power than you can use anyways. lol How does it spool from a roll? Does it take a noticeable amount of time or is it pretty quick? Thanks for the help.

Also, Shaun has a t6 turbo we will try and fit in the engine bay tomorrow. Hopefully there is room there. A front low mount was another option as I have a lot of room with the RS nose on the car.


From a roll it takes a few seconds to spool.  It is very slow and I went to the track and ran a best of 11.69@134mph @ 17psi.  I am not happy and have spoke to Precision and Majestic and both stated to try a smaller turbine housing as I have a 1.32A/R turbine housing.  That thing did not get going until the 330 foot mark with off the foot brake.   

[86merc]

From a roll it takes a few seconds to spool.  It is very slow and I went to the track and ran a best of 11.69@134mph @ 17psi.  I am not happy and have spoke to Precision and Majestic and both stated to try a smaller turbine housing as I have a 1.32A/R turbine housing.  That thing did not get going until the 330 foot mark with off the foot brake.   

See that is what worries me. My t-trim off the foot break just takes a while to get into the boost. Although my stall is real tight right now at 2500 or so. But thanks for the info. That is the kind of stuff I am looking for.