capri93

OK heres the big question with all the information I can give you.
Im having a real hard time with the numbers part of buying a turbo AR and the other dimensions.

Specs and parts I have
this is a street/ weekend worrier doesn't need to make emissions, I love PA.

87 TII 4pt plates street ported
86 housings race ported
48 dellorto carb boost preped if it ever gets to me
manuall boost controller
stainless header with t4 flange and 4bolt waste gate flange (50mm?)
large FMIC (32x12x4 i think)
FM oil cooler
electric fan
no exhaust yet (built to suit)

What size dimensions (ar# and such) should I be looking at for a turbo.
Im looking for something that will spool fairly quickly but keep making power out to red line, and is 400HP+ out of the question? Last part of the question what size waste gate should I use.

capri93

I did some looking on line in ebay and some local shops but they're all different. My local speed shop recomended a t4 with a .70 AR for like $3k and in ebay I had looked a turbo that was supposed to be just for rotarys and its AR was 1.15 and I think the price was around 300. Are there any particlular companies to stay away from and what would be a good bang for the buck turbo.
I realize that the numbers and dimensions for a turbo define it characteristics. ie how fast it will spool and how much boost can be achieved. I guess im just lost in the numbers.

steve84GS TII

If you want 400 HP or more,its time to start looking at EFI,an electronic boost controller and an expensive turbo.Full TO4E,60-1,62-1,GT Series,ect.....
The guys running some of those turbos usually get around 400HP,but Ive never heard of anyone doing it with a carb......not that you couldnt,but EFI is far better when your skirting the limits of what a moderately built 2 rotor is capable of.

Id seek the advise of the FC guys on this one,since your engine is FC based.If the FC crowd here gives you any sh*t,check out TeamFC3S.org.Lots of big HP guys hanging out there and its easier to get good turbo info there because they seperate the N/A and TII guys into camps.

A/R for one turbo doesnt mean the same thing on another turbo.Its tough to explain,but there are lots of variables,including your expectations for the turbos behavior.Two different turbos can make the same peak HP,but go about it in completely different ways,depending on how you choose your housings,trim and A/R.Its best to leave it to a pro,or another experienced turbo guy with the same engine and expectations as you....

z-beater

I agree with Steve. Picking a turbo is not an easy thing and there are a lot of variables that can play into the overall performance of your engine.

Creating hp on a carb is do-able however does not hold the prestige and or ease of FI IMO. Most(not all) carbs have a harder time holding a tune than an injector. And when you need more fuel with efi you just click a button. While with a carb you need to get out and change the jets. That being said, there are also draw backs of a FI system as well. First and foremost is the cost. It is easy to drop 3k on a good fuel system. Just for illustrative purposes here is my setup with costs. I will round figures for ease of adding amounts may vary slightly.

Fuel pump w fitting kit(a1000): $300
Secondary rail, modified primary rail, AN fittings lines, injectors(850 Pri, 1600 sec): $1500
Standalone: $1200

For a total of 3k. Granted my fuel is setup for over 600 to the wheels but in reality the only thing that you will really save on over my price is the pump. I also got all the bells and whistles with the Microtech(3-bar map sensor,Laptop adapter, etc). You could probably save a couple hundred there as well. In the end though you would be around 3k.

Now let's move onto the Turbo. Yes it is true that the Rotary requires a larger AR wheel. As Steve mentioned though there are a lot of factors that play into it though. Start researching turbos and they will become self evident.

My turbo will probably be good to just under 500rwhp at about 22psi. Here are the dinensions:

Hotside: 1.0 AR
Coldside: 61mm

There are downsides to this though. I do not see full boost(11psi) until about 3500 or so. I have yet to crank up the boost. I estimate that at about 10psi I am at about 300rwhp. I think that you will be amazed how fast that really is. Take a ride with someone local if you have the oppurtunity. Before building mine I had the chance to ride in quite a few turbo and supercharged FB's. I noticed that around 250 to the wheels was when the car really started to get fun. And with a mere 50 extra hp things could get scary really fast. I built with the expectation to grow. I think that this was a wise decision.

3k for a turbo is *WAY* over priced. You can get a 96mm turbo for less than that. If I were you I would look at spending 1-1.5k on a turbo. There are a lot of other things that you will need to purchase though. It sounds like you have this under control though.

As for the WG go to the single turbo section and conduct a search. There are quite a few options that you have. I personally own a HKS 40mm, however the Tial units are also a quality piece of equipment.

Z

No_Rotor_RX7

if you are looking for 400+ horsepower with a streetport but not having to run 25psi then start looking in to a T66 or even a T70. the GT3540, altho costing more in general, averages around 400rwhp in the 15 - 17psi range on a good motor setup. hell we got 475rwhp at 18psi using pump gas on one of our FD's with this turbo.

buuut, it's all in your budget. new turbo's with better technology/ research in to them will do what you are looking for on pump gas boost but for a greater price.


oh one last thing, in my opinion the best overall "street" turbo is a true 60-1 (turbonetics is the best on this one). you can make 400rwhp on pump gas and have great spool characteristics.

Dan_s_young

iTrader: (1)

You could check out the turbo's that Robert has (rotaryshack.com). He's a good guy, just hard to get a hold of online some times...

trochoid

iTrader: (6)

A turbo with a .70 ar will be boosting by 2k, and max out way too early. The 1.15 will have lots of lag and if it is the XS Power one, run away fast, same for the 'mechanic' that recommended the .70 one, he is sizing it for a piston engine's exhaust flow. You might spend some time in the single turbo section of the forum and look for a setup that produces hp in the range you are looking for.

If you find a good one, PM the owner and ask about his likes and dislikes of his setup. In all honesty an FI setup, running MegaSquirt will be easier to work with in the long run, produce better driveability and less frequent tweaking/tuning.

Btw, I know little about turbo setups, just read too much and have no experience with them personally, so take it fwiw.

peachykeenwight

With a Turbonetics 62-1 (.96A/R) and a large streetport at 16 psi on pump gas BEFORE the Steve Kan tune, the car made dyno-proven 409 horsepower.

Now at 13psi after the tune, it's probably the same if not better. It might not have the same spool characteristics as an GT-XR series, but I see full boost by ~4000.

The turbo was 1400, and the guys are right, you're going to want to go EFI. It'll be worth the money.