Bigger turbo on FM mani...what will fit?
 

I have the gt2560 right now @ 12 psi. If I increase the boost anymore the turbo starts to loose it's efficiency and blows more hot air( car starts pinging and etc.). I was considering getting a larger turbo. Does anyone know which turbos will mount right up to my manifold?

Thanks guys

Really? I think the gt2560 is good for more than 12psi. I'd first look into your tune and intercooler setup before getting a larger turbo.

I know people take em up higher than that 12-17 psi, but when we were tuning my car when we took it up to 14 psi it would start pinging alot and overheating. Right now my tune is awesome. Car runs extremely well( haven' seen it knock once in the last 2 months). I was considering going up to like 14-15psi with WI. I just got my new radiator in, which is helping keep my engine temps down. I think actually with my new radiator I will try to run 14 psi and see how it runs. I just was trying to see what compressors would match up to the mani. Eventually I want to get up to around 300 whp( I know there are alot more supporting mods to DD that much power). I don't think I would try to get 300 whp out of a 2560 cause the tune and setup would have to be almost perfect. Be easier on a bigger compressor and if I am going to shoot for that power level then instead of spending money on WI and spending time tuning the car more, when in the futue I will get a bigger turbo anyways, I'll just save the money for the bigger turbo.

It's about mass air flow AND boost/pressure differential, not just boost.

That is to say, a 2560 pushing 12 PSI of boost on a 2.5L engine is flowing a lot more air than one that is pushing 12 PSI of boost on a 1.8L engine.

The 2560 has been taken up to ~275-300rwhp, on a good day, on the Miata, so if you're not at that point, I think it'd be a waste of time going for a larger turbo.

I;m not sure if you have looked at the compressor map on turbobygarrett.com but the turbo should be plenty efficient to 18psi and could be pushed past 20psi pretty easily to squeeze out more power. If you don't have a built motor on the other hand, then you will need a bigger turbo to make more power at the same boost.

You want the T25 housing version of the GT3071R.

http://www.turbobygarrett.com/turbob...30/GT3071R.htm


Mark

Right. And there's a bunch of turbos from that GT3071R to the GT2554R that will bolt up to the T2 style FM manifold. If you want to keep the downpipe too, that limits the selection to some GT25/GT28 turbos.

How would yall suggest getting some more power out? Upping the boost with a good tune and possibly getting D/O WI to keep the knocking down. For my exhaust right now I am running a test pipe and a 2.25 midpipe with alittle turndown. I'm going to be getting a custom exhaust soon though. High flow cat and 3" pipe all the way back ( no muffler)

do you have any datalogs of power runs (like the one from your dyno sheet/pull)?

Ya I have it, and I've been meaning to get it and scan it in at work (and scan in my dyno) but haven't gotten around to it. I'll try to scan it in the next few days.

If you went with a full 3" exhaust I would not be suprised to see, at least, 20whp more on a dyno.

really? My exhaust is pretty free flowing right now. I thought I would get around 6-10 whp gain. If I got between 15-20 that would be awesome.

With a 2.25 midpipe thats a major restriction...I'd try a 3" exhaust before dumping money into a new turbo, might save a bit of money.

That's what I got.

wow, I'm going to do that as soon as I can get the money. It was on my list mods to do, but it wasn't as big of a priority for me.

i wanted to change my too
FM said 3071R will bolt on, just the pipe that goes out the turbo need to be bigger, which is easy todo.

Funny I wonder how I ever made 300 RWHP with a FM Mid-pipe at 2.5"?

Mark

No one is saying it can't be done, we are saying he'll make more power with a 3". We are giving him options he might want to try before laying down for a $1000+ turbo.

I'd go for the turbo anyway. :D Agreed that a better exhaust always will make more power, but my experience was a minimal increase from a 2.5" full exhaust -> 3" dump pipe on my 2560 even with unlimited dyno time at 12 PSI and under.

Mark

Yeah but the increase from 2.25 -> 2.5 will be more than that from 2.5 -> 3.0. That's where you'll reach diminishing returns on the bigger pipe.

A bigger turbo into the same restrictive exhaust he's running is an assbackwards way to do it. Upgrading the exhaust now will make him good to go when he does go to a bigger turbo.

Frank

Agreed It seems to me that your Cooling of the intake air is the major sticking point here. I would get the 3 inch done and then, i would throw some WI in the mix a simple kit with a 2 gph nozzle set to come on at 9 psi or so should allow you to run 14-15 psi with the effeciency that you would like to have. But remember when you throw in the WI you need to tweak your fuel and timming a hair to make sure you take advantage of the cooling effects. Just to be safe i would spring for an aditional 3gph jet as well. Given the effeciancy of your IC right now the 2 gph should be ok for the extra 100-120 hp you plan to push out. This is also abit dependant on your mix of methanol as well. I like 30% best but your results may vary. GL

Thanks for the help guys. My biggest problem now is that I have no cat and I have to get my car inspected within the month.... Think I'm going to do my exhaust now so I can pass. You don't have to have a muffler to pass right?

As far as i know no. :bigtu:

Clear up some confusion for me.

He's upping the boost from 12 psi to 14 psi and starting to see pinging and overheating on the exhaust charge. How can you guys tell the difference between an intake charge cooling problem and a fuel supply problem? What are the AFs and EGTs? Is fueling maxed out with his current fuel management?

Well, without looking at duty cycle of the injectors and AFRs at the wideband O2 sensor, you couldn't tell the difference between pinging from hot air or pinging from lean condition. This guy's got a Link ECU, though, so he can track AFR and duty cycle, so I'm assuming he's already ruled that out [lack of fuel].

If not, though, then you're right: he should definitely look into that.

2.5 should support more than 300 hp. I would look at the turbo like mark

jegs sells a cat for like 80 bucks. I had that on my setup and it passed in Texas. PM me about and I can give you more information

Dang, the same day you posted this I went at 7 AM to the muffler shop and got a high flow cat put in with 3" all the way back ( no resonator). My turbo is surprisingly quieter than what it was before. Before it was like a super high pitch whistle that would hurt your ears when i WOT passed you. Now it's more like a whoosh kind of sound. The car does feel more powerful though which is nice :)

Can def. see a difference in spool time as well