Red91vette

iTrader: (3)

I really want a turbo for my car, and I like a lot of the kits out there, but the price is too high, and I love designing and building things myself. I've decided to go with twins compared to a single because of spool time. Since there really aren't any twin turbo kits left, Icon seemed to be a real nice kit, but they are out of business, so I am stuck to making my own which is fine. I originally was going to work with my 91 vette, but after getting beat by an NA LS1 when I was on the bottle, I decided to pick up my Z28. I was first thinking of mounting the twins down low, just like the Icon, out of site and try to keep everything hidden, but I don't know if I will be able to fit everything down there without some serious welding. So I liked the idea of relocated the alternator for the QMP kit, I figured I could relocate that and on the passenger side, remove the AC. I wanted to keep the AC, but i'd much rather have twins instead. I was going to flip my stock exhaust manifolds around, passenger to driver sides, and see if it will all fit together if I weld up a small pipe from the manifold to the turbo. From there the down pipe could run straight back out the original exhaust route, and have small intercoolers, probably ATI's in the front bumper and the air filters where the fog lights used to be. From there, I want to have the intercooler tube come up through the air lid into the throttle body to complete the stock hidden look. I know it will be hard to miss two turbos but there are some dumb people out there and I'd love to take their money. Hopefully the exhaust manifold will work, that way I don't have to weld up too much pipe, but I haven't meassured it out yet. My concern is what turbos to go with. I am going ot be using this on a stock motor, and looking for around 500rwhp, pump gas no alchy. I was considering running an internal wastgate to save on space. I know that won't give me as much horsepower, but im not looking to set any records. I have been looking all over ebay for a nice pair of twins, t3/t4 turbos, but all of them have external wastegates. I am still unsure exactly how these style wastegates work, I was told to use them back when I was doing a setup on my vette to save on space. Can anyone shed some light on which turbo and wastegate combo would be best as far as power goes but in a relatively small package? Sorry for all these turbo questions, I just need to figure this all out before I go buying anything, thanks guys.

V8_DSM_V8again

First question

"around 500rwhp"

Um like get a centrifugal supercharger..... If you dont want more power than that stick with the supercharger... It's just too much work for the gains to put small turbos in when a big supe can do the same thing... Now for a big hp high boost 25psi I'd go turbo because of just how much more power a SC takes from a crank to run 25psi. It takes twice as much power to supply the same engine wth 25psi instead of 10... It's better to get that much energy from the exhaust to keep the losses down and sideload off the crank.

Basic comparison from a normal guy trying to decide...

http://www.turbomustangs.com/turbovssuper.htm

This part is wrong "Don’t have to worry about overspinning a turbo" you can do that... You'd need to go extreme with the overrev to kill it but you will lose efficiency below that.


Pick up a copy of car craft for the full version of this.. http://www.carcraft.com/techarticles...s1/index1.html

Not because you are swaping but because it shows all the GEN III accessory configurations... You can probably relocate things with parts from a yard and some washers for shims..

The shortest distance between two points is a straight line right? So put the Turbos in the same path the exhaust has to go anyway... Which is the incon location... . This is the most efficient way to do twins when it comes to exhaust system flow... But dont use log manifolds..

I'd start with a set of mid length headers and go from there for the exhaust... You could just run a short length of collector diameter tube off the mids with a T4 flange on it and run it to the turbine just a short pipe to route the headers to where the turbos fit... Should'nt be to hard..

Run the waste gates back into some 4" dual exhaust 18" back probably just before the H pipe (X is a waste on turbos does nothing an H cant) then run two 4" magnaflow round mufflers with side exits before the rear wheels...


With rear low mount twins the exhaust side is simpler... I'd take the KISS further which is why I recomended a side exit to keep the system length short and bends to a minimum... It works... Less bends, less pipe = less drag at the same diameter..

Twins also have two thrust bearings to distribute the load of the same compressor and turbine wheel area that a big single puts into one thrust bearing.. They last longer... Just get the garret "360* race bushing" CHRA's they are harder for a beginner to kill. BB CHRA's can be over oiled without a restrictor and a little dirt can plug the restrictor and kill the bearings...

There is more intake and IC plumbing with two.. Splicing 3" aluminum mandrel bends with silicone couplers to plumb a filter to each compressors inlet is good enough. I'd run two small air to water IC's and a heat exchanger since you are thinking sleeper...

Red91vette

iTrader: (3)

I am just looking for 500rwhp, for now, future plans of a motor build up and well in excess of 500rwhp. I would rather have a turbo then a supercharger due to driveability, and the uniqueness of having a twin turbo Z instead of all the other blown ones out there. I can have near stock driveability with turbos as long as im not on the gas.

Your idea of using a mid length header and just basically bolting on the turbos from there is a lot hard then you think. There is not much room or ground clearance down there. That was my original plan until I actually measured out the area, and unless I make custom turbo manifolds from scratch, theres no way that could work. Also, the IC and air filter piping could not fit unless I run it under the Kmember, which I am not about to do since that would be the lowest point on the car. The reason I like the idea of placing the turbos where the AC and alternator are is because the ease of the rest of the installation. The downpipe can go straight out the back like a normal exhaust, I'd run full exhaust with cats and a muffler, but have a cutout after each turbo. The intercooler and intake piping could easily go to the front of the car in the bumper for more air flow and not have to go under the Kmember, so I wouldn't sacrifice ground clearance. I am going with an air to air because the car is going to be a daily driven car, I know air to water is more efficient for the track, but I am after a quick reliable street car that performs as well on and off the track.

The only easy way I see of mounting the turbos down low is if I get a hold of an incon kit, which I doubt, especially since I don't have the money for it. So right now I guess my options are open, and to me it seems like the best and cheapiest way for now, is to use the factory exhaust manifolds and remove the AC.

Thanks for your opinions and advice, can you give me any info on what small turbos I could put there to save on space? Im not too familiar with internal wastegates and how exactly to regulate boost with them. Thanks.

V8_DSM_V8again

Alot of the points you make are very valid reasons to go turbo... Thats why I posted the pro/con link.... I'd probably go with a pair of medium sized turbos... unless high boost (25 and up) is your goal.


It's all about matching the compressor wheel for the CFM and pressure ratio you will run at.. The compressor wheels in the PTE TE44 and TE60 will like pumpgas boost levels alot more than the PT61 56 trim... There is no reason to run the PT61 if you are only running 15 psi max.. I dont like the on center turbine housing PTE's come with and even if I ran an external gate I'd run a different one.. But the specs on the comp and turbine wheels are what I would suggest.. I know of a reasonable shop that can build them with the bullseye housing. The compressor covers are the same size on the PTE stuff... If I can fit it can fit between a DSM's stock radiator and fans and the block it can fit incon style on an f-body... I'd run the bullseye T4 turbinehousing because it's internal gate is huge and works well. It is also a tangential housing as opposed to on center.


http://harlan-engineering.com/incon/incon.html
A tubular K member will help clearance wise.. Look at the INCON installed pics.. I think you misjudged some things. The turbo location is a good one I just don't like their soft pipes... Hit up search and find the incon pictures.. There is an entire photo album showing them on an LS with the trans pulled so you can see where they sit in relation to the floor pan and block on each side.. The passenger side huffer hangs lower than the drivers side.






It may take more work on the headers.. Like cutting the collector off on the drivers side, triming the tubes down and putting on a t4 flange collector to mount the turbo direct to the abbreviated mid... Maybe doing the same on the other side with some mandrel bends on the primaries then weld on the T4 collector ETC.. The Mids will be close from the Head towards the bell housing... It's extremely faster to modify them than to start at the head from scratch and weld back. Alternately you could start with corvete exhaust manifolds and run a section of pipe back to the incon location..



Don't rule out a streetable air to water.... Everybody knocks it... I have seen the same cars with the same turbos but A2A vs A2W... With a good front mounted heat exchanger it still beats an A2A w.o icewater...

Just use the wastegate as a cutout... There will be seperate tube coming off the wastgage ports just put a run of pipe and a turn down on it. When it reguates boost it will just cutout.. You can also put a bullet on it before the turn down.. Cutouts will work but going huge with the catback will maintain the sleeper like feel by being low key.

The Low and rear turbo location puts the turbine outlet and wastgate spouts in about the same path as mids would be on a NT. Upfront runs exhuast forward and turns it down and around to go back again... High front the intake and IC are easier... The rear has a better exhaust path.

Red91vette

iTrader: (3)

Im still a little confused on which turbo to go with, I have never heard of a bullseye T4 turbo before? Are most DSM turbos internal wastegates? I rarely see and external wastegates on any stock turbo car. So maybe soem upgraded DSM turbos would work well in my situation. I don't plan on running more then 8psi on my stock motor, once I get a motor build up, I will swap out turbos, maybe the whole design and run upwards of 15psi. Right now though, I just want stock driveability but with the push of my right foot, 8psi worth of about 450-500rwhp.

I plan on getting a tubular Kmember, A arms, and motor mounts to give me more space in designing the manifolds. I haven't seen a really good picture(s) of the incon kit, all I knew is the turbo was mounted down low and close to the block. I'll have to do some searching around, the link you gave me, the picture is too dark and you can't really see anything. I want to get a good look at the design of the manifold and the intake/air filter piping. I could see fitting one or the other through the kmember up front(eitehr the IC piping or air filter piping) but I don't see how both could go through without sacrificing ground clearance(I must have misjudged something things).

As far as using modified headers, that won't be much of a problem, cutting them up and welding different pieces together to make it fit shouldn't be that big of a deal, I just have to touch up on my welding skills. I'd like to get 321 stainless steel, but that stuff is looking pretty expensive, what would you suggest to get material wise for the turbo manifold extensions? Keep in mind how hot the turbo manifolds get(im sure you know this) and that im on a budget. When I was going to twin turbo my corvette, since it had the typical small block style heads, they made header flanges so you could weld up your own custom headers. I was going to get those, which are basically a 2" extension from the head, and weld up my own custom turbo manifolds, similiar to the calloway style manifolds, mounted down low. They unforunately do not make such a thing, that i've seen for the LS1 style heads. Which is why I wanted to use factory or aftermarket exhaust manifolds as the base and build from that, but the less welding the better.

As far as the intercooler goes, I am going ot stick with a good A2A front mount. I know how well an A2W works, but the camaros have a huge front bumper which would fit a perfect front mount in there and that would just look mean as hell, the only thing wrong with that, is there goes my sleeper look, but hello intimidater look! When I plan to swap out the turbos for bigger ones and run 15+ psi, I will probably switch to an A2W intercooler and through an automatic in, then the car will be mainly a drag car with very little street use, which is the complete opposite of what I want now, a drag car with daily driver manners.

What do you mean have the wastegate as my cutout? I plan on running the wastgate to the atmosphere, is that what you mean? I am just going to dump the wastegate right out underneath the car, not even bother with it running back into the exhaust. So if I do run an external wastegate, it will be mounted low and the output side of it will face the ground.

It is really a toss up between the two turbo locations, down low is easy on the exhaust side while up front or up high is easy on the intercooler air filter piping. Well right now I am not ready to do the kit, I am just getting ideas and collecting parts, maybe this winter I will start to design and mock up the kit, but for now I am just doing my homework and researching everything I can.

V8_DSM_V8again

It may be the same compressor wheel, turbine wheel and compressor cover as a some DSM garrett hybrid turbos but it wont be a hybrid or really much to do with mitsubishis because it will have a garret bolt pattern T-4 turbine housing... Bullseye really just makes a few different turbine housings which are the exhaust frame of a turbo... You will want the T-4 version... See how much bigger the inlet is their T4 one vs the mitsubishi or T3 one?

http://www.bullseye-power.com/index.php?cPath=22

T4


T3



Mitsu



Yes run 321 some 321 in what ever shape and length to weld on the primary tubes to move or point one of these where you need it on each side...



If you are running a tame low-mid boost setup just save some money an run corvette factory manifolds.... They even worked on a high boost high end single turbo motor....

Yes and you can just dump an internal gate just like you talk about with an external..

Hey if you want an atmospheric dump on a 8-12 psi engine while I run a massive full exhaust for a reasonable price on a 25 psi full tilt monster without choking it.. It is your choice....


I think you should build an engine first then Fab up your turbosystem on the engine while it is on the stand. You waste big $ by going small turbo different IC then changing to a built engine with bigger turbos and changing the IC. etc...

Pick one direction... Get all the parts, plan design and build each subsystem to work as a matched full system then and only then install everything...

Red91vette

iTrader: (3)

I looked at that site, ive seen the garrett TO4B turbos before, they seem really nice and would reach my goals. They have internal wastegates so that would save on space too. What is so different from the Fbody manifolds from the vettes? I wanted to do a full custom manifold from 321 stainless but I priced it out and it is ridiculously expensive. Maybe I will just save up for the meantime and try and find some incon manifolds for sale, incon parts are always floating around. As far as the motor build up goes, it would be pretty hard to piece together a turbo kit with the motor on a stand. I wouldn't know where everything else is at etc. But for right now, there reason I am doing a twin setup on a stock motor, is because I don't have the money, and I want something that I can drive daily. When I have the money for a motor build up and a new setup, then the car is going to become mainly a track car, and only see some street use, it won't be my daily driver car by then. btw, thanks for the replys and advice, you seem to be the only person who really cares about people that dont have 10 second cars, everyone only replies to people who have insane amount of money dumped into their cars and are putting up 700+ rwhp and running 10's or quicker, but not the people that are trying to get there, doesn't make much sense, oh well....

Pro Stock John

iTrader: (34)

Incon setups work pretty well and I've seen them make 400-500rwhp with a bone stock engine no problem.

Evil F1 SS

PTK is about to offer a twin turbo kit for the F-Body

smokinHawk

iTrader: (48)

if your planning on doing money races keeping your set up quiet why not just go nitrous?
fro one thing you said your fabbing up a kit becasue the ones out there are to expensive. Well fabbing your kit up will cost just about the same.
one option is to get the sts kit or used TTi or qmp kit, those can be had cheaply now when they come up.

though for your plans and goals i think a goood heads/mild cam/bolt ons + spray would serve you best, and be with in your budget.

getting a working turbo set up isnt easy.
also with the super charger you still have your driveablitly intact that should remain an option as well.

JZ 97 SS 1500

iTrader: (2)

PTK's kit will be single for the F-body, but twin for the C5 and GTO.

Jose

V8_DSM_V8again

Hey... 91 I mean by fabbing on the stand is leaving the stock block on the car while building a another complete engine.. Check your mounting and clearance both on the engine in the car and engine mounted on the stand...

The same turbo setup can make alot more power on an engine with a CR that has been dropped and is also slinging forged pistons...

Maybe I'm just resorcefull and innovative because my costs will dwarf the kits...