All those GT35/40 turbos out there and not a single 500rwhp dyno on this "700hp" turbo, What gives? Has anyone dynoed at 20-24psi on a GT35/40? Rotor motorsports, comment? I imagine the 700hp is flywheel@13:1afr Anyway The general claim is equal power to a T78 with better spool. Anyone want to back that up? Anyone running a T66 1.00ar Q trim? Dyno? Is anyone out there running a turbo capable of 500-550rwhp@20-22psi? If so do you have a dyno? I know you're out there.... Here turbo, turbo, turbo...

Carl cbyck@attbi.com

 

Why would Rotor MotorSports comment? If you want to pay him some money so he can run off with it, then I am sure he can comment on how you can make 2,000 RWHP.

 

The GT35/40 does sound like a nice setup, but I think people throw around HP numbers for lean burning piston engines with much lower BSFC numbers. Same problem with fuel pumps, etc. So, say the GT35/40 is a 700 flywheel HP turbo on piston engines. Multiply by 0.55/0.65 to adjust for the BSFC on a lean-burning piston engine versus a rotary running rich enough to live for a while. Multiply again by 0.85 to account for drivetrain losses. What does that leave? 503 RWHP.

Don't get me wrong -- since this is more HP than the vast majority of people will be running, this still seems like an excellent choice of turbos to me. And 500RWHP would make one hell of a street car.

-Max

 

I would love to have a street car with 500 true HP

 

when a turbo is rated at 700 hp that doesn't mean it will make 700 hp on a 13b rotary. If that were true you could bolt it on to a pinto and viola, 700 hp.

what it means is it is capable of that much power on an engine with already , say 500 hp, the turbo simply has the flow capability to add 200 hp to that motor. If you bolted it to a 800 hp nascar v8, it would choke the exhaust and not add power.

 

HP ratings for turbos are based on how much air the turbo can flow efficiently. My guess is that someone chooses an efficiency level and then looks at what the max flow is for that efficiency level. With that flow number, they convert that to fuel flow by applying an A/F ratio, and then calc power by applying some BSFC. Since the A/F and BSFC (which are themselves quite related) are likely chosen to make the turbo seem capable of big power, they aren't appropriate for a rotary. A rotary makes less power for a given amount of fuel, so even if you could get the rated number on a piston engine with lots of ping tolerance, you aren't going to make the same numbers on a rotary.

HP ratings for turbos, fuel pumps, etc. should not be relied on when it is really time to choose components. Get the real numbers and do the calcs yourself, or look at what other people have experienced with the parts you are considering. HP ratings are specifically worthless for choosing components for rotaries (without applying some mental conversion factor), because rotaries have different numbers for BSFC, etc.

-Max

 

Max, you need some help with your math???
hehe
In my mind there is no substitute for this turbo...although T04-R's keep bouncing around in the back of my mind

 

Carl - How many times have I told you? A777 is running 10.22 @ 133mph in a 1st gen with a GT35/40. The car is making more than 500rwhp and on around 20psi as well....

 

AJC, I hear you, and I continue to seek more information, so that I can make a good decision. there are alot of options out there and I don't want to do this three or four times. So many of the big HP cars have gone through two three or more turbos searching for the level they want. By asking the question more than once, I have recieved many different reponses, and varied advice. Isn't that what the forum is for? If you look at the variety of responses to my posts you will see the value in asking more than once. Also I have never seen a 500hp dyno on th 35/40 from anyone, so for purposes of a several thousand dollar investment I have only one example to go on with little actual documentation of how the power was accomplished. I do not doubt his accomplishment, but as an example I have seen to dynos of 430hp, one at 10psi, and one at 15psi. Obviously something about the setup of these two cars is different. I don't think I can learn too much about either by asking more questions. Is A777 streetport, bridge? what other mods? Please don't be frustrated by what seems to be a duplicate post, if it makes you nuts just don't read it. I appreciate your and everyone elses input, and will continue to ask questions until I am confident that I know how I will reach my goal. Thanks for your help, Carl

 

People have only started using the GT series turbos in the States in the past 6 months or so. If you are not comfortable being one of the first to use them, don't. Go with what people have used in the past and have been suxccessful with.

What turbos have been successful? Go and have a look through the Single Turbo setup post that is stickied at the top of this forum. Im sure this this question can be answered by one of the 120 posts in that thread.

 

AJC, I have nothing but respect for your accomplishments. I don't have any problem with "being first" BUT, like I said I'm going to do this once. I'll do lots of research, ask lots of questions, and take my time to arrive at the right combo. BTW do you know of anyone running a GT40? Too big ? Like I said earlier. I'm seeking the most up to date info I can get so that I end up with a setup that meets my goals. It sounds like a777 has shown that my goals can be met with this turbo, and I'll contact him for details. I would imagine at one time you asked alot of questions too... Thank you for your advice. Cheers, Carl

 

Well, if your good at math, you can tell me how much power Im putting down. I ran 10.73 @ 128mph running 20lbs of boost on a stock reman. My A/F was 11.2.1, very rich......to be safe. Im not being sarcastic, but what do you think Im putting down if Im running 128mph traps??? I've yet to dyno, still scared I suppose.

 

there are so many factors in determining hp that it's impossible to say what hp a turbo can put out. they just came up w/ the 700hp number from the compressor flow rates. the gt3540 should max out at around 70cfm and hp is determined by roughly multiplying by 10. there are so many different factors though, from turbine housing size, to porting, to tuning, etc. it's literally impossible to get a concrete figure. however, simply from physical comparisons, 500rwhp would seem to be the limit of this turbo. comparing it to a t78, it's got a smaller compressor and a much smaller exhaust side. you don't see too many people capable of making 500whp on a t78, and a gt3540 will make a little less than it.

 

I think you should change the title of this thread to 'GT35/40=500rwhp, uhhhhh.....yeah!'

nocab72 put down almost 450rwhp @ like 15.5 psi. How in the hell could he NOT put down 500rwhp @ 20+ psi?????? The facts are there bro...the GT3540 will make 500+rwhp. There is no debating it. It is fact.

 

I agree with Gotboost, obviously the guys only running 10-15 psi were not running race gas, but still posted mid 400rwhp levels. With gas like c16, they could have easily turned up the boost and posted in the 500+hp level. What's so hard to believe?

 

There will be a 35/40 dyno today, will post results later.

 

Do you know who tuned the timing?

 

Just stirring the pot really.I think the 35/40 is probably good for +/-525rwhp, and I am ready to order a GT35/40 from RPM, just trying to get a read on proven power ability of this turbo. My goal as anyone with a computer now knows is 550rwhp, in a turbo usable for road race.I just continue to make me wonder why no dynos from 35/40,T66,GT40, are posted showing their capabilities. I know several of you are working out some bugs, but there's more than two guys running these turbos. I think A777, and Ernie are there, I think a couple of guys are right there with T66s,as well as a couple of others(no dyno sheets though). RPM recommended the 35/40, Precision recommended a straight GT40 .77 inducer,.82 exducer, don't know ar(available January). Horsepower in a box suggested the alternative of a to4 with a 1.32ar, and a T66 compressor in a .70 cover(they prefer the GT, but state it is not currently available). HP in a box also stated that they felt a GT40 was too large. Another turbo I was considering before the GT was a T66 1.00ar Q trim. Calling all cars, WHO IS MAKING THE POWER??? Talk is cheap, dynos cost 150.00, I know. H88fc3s did excessive ever dyno your car? I checked the Holset website, and they list an HX80,82,85, but no 83. Must be a hybrid, how does it perform? Is that the SR stage 2 that Ernie's running? I talked to someone who took the stage 2 apart, they said it was larger than a T88! This is information the whole community can benefit from. See the site at http://www.moreboost.org/turbos.htm
Such a site would be an invaluable resource for rotary community. We could model our site after his, I would be happy to help compile the data, and then we just need someone to host it. Years ago a 500hp Supra was a big deal, now it's barely average for a single . Information sharing is the key, there are very few secret setups in that community. My point is that we can all benefit from each others research and experiences. Best regards to all, Carl Byck

 

Be patient...I'm sure someone will dyno a 35/40 with race gas soon enough. Installing and tuning a single turbo isn't as easy as many think and I've been working out bugs for weeks. After four weeks, I'm maybe half way to where I'd like the car to be. These things take time. Lots of it! I never really understood why people who just had a single turbo installed didn't hit the dyno first thing. Now I do. :-) My first run at the dyno was 1.5 hours of wasted time as I battled boost spike and an exhaust leak that threw off may afr's.
Michel

 

Math check:

Rated HP = 700
Adjustment for BSFC diff = (0.55/0.65)
Adjustment for drivetrain losses = (1-0.15) = 0.85

700 * (0.55/0.65) * (1-0.15) = 503 RWHP

Nope, my math is fine.

-Max

 

Why?

 

I know, My setup has 20 hours of tuning alone in it, Just time to go bigger > Carl

 

Ernie,
I say 485/490 rwhp...Impressive power considering a reman and the A/F...

 

Z spoke before confirming with me that I was going to dyno today...If I had I would have been limited to about 15.5 psi as @ 17psi I'm running out of fuel (100% INJ duty cycle). I already know those numbers, so I figured why risk it, why bother.

I should have another chance to dyno next weekend, between now and then if I can complete some fuel delivery upgrades, install a 3bar map sensor, put a new clutch in and do a bit of tuning I'll have some GT35/40 @ > 17psi of boost numbers for you all!

(now I just need to figure out how the hell I'm gonna tune the car @ 20psi on the street (before getting on the dyno) considering I can't keep it going in a straight line in 3rd gear @ only 17psi @ WOT...hahahah)

K

 

Nocab,
Are you streetported..? Also, what injectors were you running that you were @ 100% duty cycle (size) ..? Lastly are you running pump fuel @ 17 psi..? Thanks..