Ok I have done the search, looked through most of the posts, etc. I need some answers from the folks that have done the swap already...

Questions:

1) what tranny is everyone using?

2) routing of the exhaust pipes from the turbines, did you go with true duals or 2-1 somewhere under the car?

3) Differential and gear changes (does the stock 10 bolt make it)?

4) Driveability issues?

I have most of the engine, and the body stiffening figured out. Manifolds are being custom made, as is the intake. Just need some pointers for the rest of the system.

 

Alright, i've got a pretty good idea for most of your questions so hold on. The tranny depends on what you're searching for. If you want good highway mileage a built 700 can hold up just fine. If you dont care about highway mileage go for a turbo300 or something of the sort. Or you could always put a manual in there if you REALLY wanted.
As for true duals this question has been asked about a million and one times. Because of the nature of the turbos I THINK (someone correct me if im wrong) There wont be as much exhaust, so you wont need some massive pipes. Anyways, you can flow as much through a single 4 inch as you need. True duals are more of a i told you i could do it thing, and they have a certain cool factor to the.
Your rearend can hold up to over 1000 hp, when you start putting power to the ground ... that's another story.
If you have a borg warner these are said to be pretty damn tough, im not sure how tough though. In my personal experience i've known the rears in third gens to be pretty weak. You never know though, your rear might hold up forever its sort of living on borrowed time. This is assuming you are making some serious numbers. Turbos are excellent for driveability, you can turn the boost WAYYYYY down when you're driving on the street and it can be as dosile as a kitten... Turn the boost up for some serious power at the track. I think i've covered most of it. I'm not an expert in any of these fields so its pretty much opinion.

Gta-Paladin
aka Thanos

 

Ok lets make this a little clearer for folks wanting to read this for the future.

1989 Pontiac Trans Am GTA w/ 5.7 and all the goodies on that model (T-Tops,A/C, power everything, 4 wheel disc etc.

Engine will have 2 TO4E/T3 Hybrids, Custom intake and runners flowing around 1300-1500 CFM, 83# injectors, custom cam from a manufactuer yet to be determined. Dart II or Brodix heads, Eagle Con rods, TRW or Wiseco pistons, Custom Exhaust Manifolds (stainless steel) 58mm throttle body. Haltec E6K engine management system or SDS engine management (if they ever come out with a data logger) SFC's, still toying with suspension and driveline as you see above.

This is a budget buildup, meaning parts are a hard thing to come by where I am at, so the car has to be built right the first time. I am currently serving in the miliary in Okinawa Japan, and F-Bodies aren't exactly sitting in Junkyards to start with.

So I am asking the guys that have done this what worked, and what didn't.

TC

 

If it's a cost thing, why dont you get a grand national engine? Theres a post around here... It can be done for 3000 dollars and run 12's tha'ts not that bad in my humble opinion

 

It's probably that he's stationed overseas thing... meaning that there is a quantity of about Zero (0) American vehicles willing to give up a Motor. And forget about the mailing system unless you could see spending more than a few Franklin's on shipping a used motor via UPS, FedEx, etc...

 

Sorry this has nothing to do with your question but is this Sean? (sp?)

I know you know the "Skyline crew"...lol! (danny, wes, brian aka speedy, etc...). You probably don't remember me but I was always helping Danny and Wes with their Skylines even if I didn't own one. I remember your handle on teamnismo.com also.

Didn't know you were a thirdgen guy! I know which GTA you're talking about too. It's that gray one right?

Just curious you said you were going with a custom intake...are you doing a carb intake converted to EFI or sheetmetal??

As far as tranny reliability goes, it seems the 700R4 is a hit or miss deal even when built up. If you plan on a lot of drag racing (or even cruising) a Turbo 400 with a Gears Vendor overdrive is the way to go.

Don't know if you wanna keep the AC (not a bad idea in Oki) but with twin turbos, you may not be able to...just something to think about.

Anyways I'm PCSing Jan 5th. Danny and speedy were talking about getting together one Sat night and just staying out cruising/racing til 0500 (with this BS curfew and all can't afford to get busted!)

 

blah

 

Yeah its me. I picked the car up with an expired JCI for $175, been toying with the twin turbo on it for about a month or so, all the parts are coming together a lot easier than i thought. Picked up the 83# injectors for it yesterday. The custom manifold is being done by Motorworx, they did the 20b intake for Beau on his RX-7 and the thing is beautiful. Uses the 58mm throttle body. They will also be doing the headers similar to Grapape's setup posted elsewhere on this board. They will be a stainless steel design. May be a little more expensive but definately will look better. Looking at Haltec E6K or Electromotive Tec 2 for the management, as I don't care for the Accel DFI setup.

More to come as things come together.

Sean

 

You'll want as large an exhaust as possible. The backpressure after the turbos kills performance and makes the system hotter. It slows down the turbo, and adds even more backpressure between the turbo and the heads. Go as large as you can fit. It'll really wake things up.

I'm currently running 2.5" downpipes from each turbo to a 3.5" y-pipe. The new engine combo will have 3" downpipes, exiting out the side in front of the rear wheels. HTH.

 

Did you say Budget? LMAO there is no such thing on a project like that. Why go twin turbo? Spend some money and buy a T66 or T76. You'll have way more room under the hood and with the right parts there will be Zero Lag. I know a guy with a TPI 305 (Not Stock) with a T76 running 9s@136+ mph in a daily driven street car.

Twins are a waste of time and effort and make the car a biatch to work on. Also 83lb injectors? Jeez why so big? The bigger the crappier they usually run at lower speeds. Tek 2? Save yourself the tuning hassle and get a FAST system.

If this is a budget buildup I hope you have more than a few grand to throw at it.

 

Ok I started this thread to ask a few simple questions. Being overseas and not being able to call up the 1-800 numbers, not go to a track that might have someone there I could talk to I am asking here.

I am not ignorant when it comes to turbocharging. I have been working on turbocharged engines now for about 2 years. I understand the arguments between Singles and duals.

I am building the car as a project, I hope to be completed by Sept of this year. Due to the location I don't readily have access to go to the local junkyard and just pull something. A lot of the stuff I have to work with has to come from the US. Shipping a TH400 Tranny is not the cheapest thing in the world. Budget is a term used loosely.

The promary goal is to use this car in Street drag runs and the occasional 0-150 meter drag races they sanction here (slightly less than a 1/8th mile) This vehicle has a purpose, It will be the ONLY american car at these drag races.

The reason some of the parts are being chosen as large as they are is for future upgradeability. The 83# injectors were bought for this purpose. As far as the management system. I have dealt with the SDS and I am impressed with its abilities, But it lacks the datalogging capabilities I am looking for. If I wanted to go all out I would go with the MoTeC system. But Not every person has $10k to throw at a tuning system.

As many folks have found out there are drawbacks to the twin system on an F-Body, space is the largest problem, creature comforts get lost etc. I know this will sound harsh, but I paid $175 for the car remember (can be seen at http://briefcase.yahoo.com/thecamel1 in the GTA folder)
Dropping $8000 on this car in the next few months is not too big of a deal to me, Spending it right is. I will be doing a lot of custom fabrication on this unit as many before me have in their projects.

What I am looking at is tried and true setups for the questions I have asked.

I looked through a lot of the older threads only to see too many people steer onlookers away from the project. Don't do this, dont do that etc... I want the people to see you do not need a Gale Banks kit, or anything to create the car of your dreams.

The problem currently is getting the correct transmission for the application. Jericho and Lenco are options but not exactly what I need for this to be street driven. TH-400 is another choice but access is limited to all of these.

This will also be an ongoing project for a few years. I have 3 L98's accessible locally, but the machine shops here are anything but adequete for my needs (not a V8 torque plate on island)

This is why I asked the questions I did, all I wanted were some answers.

I currently drive a Nissan Skyline GTS-4 (little AWD brother to the GT-R) Its by no means a Drag car, and I could never afford to make it close to competitive here either. Going to a local Street drag here is 500+ hp GT-R's, RX-7's and Toyotas of different makes. Street Driven 700+ hp GT-Rs are quite common here acctually (12 or more currently run the street drags) I am building this to show them that a V8 with the same Twin Turbo setup can be built for far less than what some of these guuys have invested in their rides.

TC

 

Heh Good Luck....

 

Well, I'm not sure what everyone else is using, but I'll give you my opinion on what to use. I plan to build a turbo 350 as well and I asked the same question a while ago. You can check out the thread here:

https://www.thirdgen.org/techbb2/sho...&highlight=t56

I plan to use a manual tranny for my project. I choose the T56 manual because I plan to do more than just 1/4 mile (heh!) and you can control your revs way better with a 6 speed than an auto. And when you have a turbo and have to deal with the lag being in the 'zone' really matters (as im sure you know). I also choose to go with a T56 because thats what they used in the Lingenfelter Corvette and it didnt blow up. As stated in the thread above (thanks guys!) you will need to beef up they tranny a little with better components. Recommended was a lakewood or bob wier's bellhousing, a hydrolic throw out bearing, ram or macloud street twin clutch, a carbon fiber driveshaft (andre already twisted his 1LE aluminum driveshaft on his turbo sbc), a ford 9" or a chevy 12 bolt rear end (sorry the 10 bolt prolly wont handle) as well as better subframe connectors and some suspension mods.

As far as routing the exhaust, I think with a turbo setup you just need a downpipe (no y pipe needed) but dont quote me. Thats what they do in all the 600+ hp toyota supras (which I think could be most powerfull turbo cars on the road when highly modified .... except for a turbo chevy!! hahah).

Dont think the 10 bolt will handle anything above 600 hp.

As far as driveability, I dunno whats its like driving around in japan (stop and go?, long stretches?) but I highly recommend an electronic boost controller so you can turn the boost down when you're not racing and take it easy on the engine.

So are you going to be selling your skyline? I live in Hawaii and just recently we are now able to import skylines into the islands through MotoWorx and Atomic Performance. Might be interested if the price is right.

Shootz

 

Thanks for the reply.

I opted with the TH-400 as this will mainly be used as a Street/Strip car and will require a lot more abuse than the 5 speed clutch is gonna like. The other reason is that it was free.

I'm trying to find the weak point in the differential, is it the carrier, the gears, the posi unit etc. Upgrading the differential to a 12 bolt or 9" is not an option.

I can't tell what I have as I cannot find the RPO anywhere in the car. I am assuming it is the 9 bolt BW unit since it is a GTA with rear disc's But I don't know (HELP!)

The Car will start life with the 700R4 installed, that way I can give folks an idea what problems to look for in future buildups.

Subframe connectors are a definate, as is the new torque arm.
The exhaust routing is the biggset question I have because I can't just run the car down to Midas here and have an exhaust hung on it.

reading past messages on the dual exhaust folks say they have had easy results using the spohn torqe arm, because of its relocation, but I have not seen anyone say that they had the subframe connectors as well. Looking at the pictures spohn has of the routing of the SFC it makes the routing I was planning a little more difficult.

And sorry but you really don't want my beater, LOL


TC

 

All you do to see if it is a 9 bolt is count the bolts on the rear end housing.I have one with 3.70 gears.I dont know where the weak link is Iv heard it is the pinion.THere is a guy whoe post in the transmission forum who sell gears for this rear end and the pumkins.I dont knwo if they are beefed up over stock but check it out.Just stay away from full slicks until you are sure you have eliminated the problem.I went 1.7 short times and 12.6 at 111 with my 3.70 and never had any problems.To tell what gears you have in the car is easy to.If you still have the 7000r4 in it,tak it on the highway at 73 mph in 3rd gear,the rpm will indicate the rear end gear.3.27 and over you can install the 3,70s which at the time I purchased them was the highest you could get,but that guy posted he was selling 4.10 ratio now.under the 3.27 usually 2.77 which I had you need a new pumkin.I ended up scoring one out of a Iroc with 85,000 on it,for $85 bucks.I never had any problems.If you do get a rear pumkin out of a bone yard,and are nervous about it you can add 2 bottles of that limited slip oil,makes the clutches slip more on acceleration so you dont shock them as much on hard acceleration.

 

I think twins will yeild you more room,if you get turbos with wastegates.Their is a company working on a system now,CAS.He told me he wants to do twins.Kit will inlcude everything for around $4000,and in ss to boot

 

well if you dont push the boost too high, I think a beefed up 10 bolt will be fine. with stock engine internals I wouldnt run more than 6-8 pounds of boost witch should be somewhere in the 400-500 hp range. and for the exhaust, I would ask sme of the local tuning shops there in japan. they know more about turbo setups than anyone!! I dont think conventional exhaust ideas apply with the turbo setup, its totally different. you will prolly have to have a custom downpipe made. ask the turbo import tuning shops but if I were you I would try not to mention you're turbocharging a domestic v8 cuz they might not like it. hahahha

 

I can weld the pipes in, thats no big deal, I just wanted Ideas on how the twins were routed with the equipment on the cars. Dual exhaust will definately be needed. The problem, is that in Japan the exhaust HAS to run to the back of the car and out the rear on a passenger vehicle... I may have to run this thing illegal.

I am asking on the Diffs because I may go to a locker or even a spool (yes I know the spool isn't streetable) But id the weak link is the carrier or the pinion than just a gearset may be the easy way.

TC

 

or you can always run open exhaust and just weld some pipes and tips under the bumper! lol!!!

 

Your rear end is probably a BW 9 bolt in an '89 5.7 car. The 90 and newer 7.625" units are stronger if you can get reasonable access to one. Or a 7.5 unit from a 5.0 car and upgrade it from 26 spline to 28 spline with a 7.625 diff (stock or aftermarket) and axles (also stock or aftermarket). Aftermarket parts will usually be better of course. Even with better axles and differentials these rear ends are pretty weak. The weakest link (especially on the BWs) are the side bearing caps and bolts. If you can scrape up a set of billet caps and studs that will help. You can see more about it on this post from the suspension forum: https://www.thirdgen.org/techbb2/sho...threadid=74280

As far as exhaust goes, how about a large single, like a four inch round (Mufflex Performance makes some catbacks in 4") or a custom fabbed oval tube unit Like used in many road racing apps (you can get straights and misc bends & round to oval transitions & mufflers with oval inlets and outlets) in a size like 3" x 6" or 4" x 6" so. You can get oval stuff from Spintech Mufflers Then if you need even more flow when at the drags, weld up a "dump pipe" system into the exhaust in or near the downpipes. You can use header colecter type flanges on the ends. Cap them off for normal "legal" street driving. Uncap at the drags. You can fabricate dump pipes for each turbo in front of the Y pipe collector for max flow when open. Exit them from under the car in an accessable area, maybe in the front wheel wells or below the rocker panels just behind front wheels. I've seen them exit in front of the front wheels too.