That may be but he did say UNLESS the twins are shot why bother.



And he is wrong. I've seen plenty of single turbo cars make the same power +/- a few hp as a well tuned set of twins. I'm sure you have too.

 

Well yeah if you put a small turbo on. I think a to4b makes about the same power as the twins. And there is always the bnr stage 3 twins that apparently make alot more power then the stockers. But anything around a gt35/t60-1 and larger should be making more power then the twins. Shoot i suppose someone could remove one of the stock turbo's and call it a single turbo. So yes not always will a single make more power even at the same boost level, but i think what most peoples idea of going single makes more power. Howard coleman has twin turbos that will make more power then most singles but i would still put it in the single turbo section. There are obviously alot of variables in answering a question like this. So i will reword it, a properly sized and tuned single will make more power then the stock twins. That is all the reason i need to go single.

 

I don't argue the point, but here's a good example, I had a customer buy a 35R kit years ago, put it on a freshly built mandeville motor, tuned by the great Kan, and he called me up saying he made the same hp as on his twins before he paid all this money building his car. We brought the car here went over absolutely everything (very well done car) put it on the dyno and made 2 more hp than Kan. So essentially no change. 336whp@14psi. There was nothing wrong with the car. It had a proven setup with proven parts, proven engine builder, proven tuner. Made the same power as his twins.

I'm in no way arguing with you. I'm single turbo guy all the way. All this talk about under certain conditions is moot to a point. It's like wanting your correction factor on the dyno. I agree they have a purpose. But truth is on that day in those conditions that is what the car put down. If I drive it to denver it obviously will not put down the same numbers.

 

This is a sticky topic...

If everything is the same the amount of air is the same too.. 14psi with either turbo would be the same.. Problem is they won't be..

The most important one that most seem to forgot is the eff of the engine will greatly change once you remove the stock twins and put on a properly sized single.. The engine breathes thru the turbine of the turbo and once you free the restriction of the stock twins power will go up.

 

Why did his car make such little power? There must be some reason.. If his engine had strong compression and everything was done right there must be something that was limiting it. I mean thats like a good 50+ hp shy of what most people make with that kind of setup. Ps what is a mandeville motor?

 

he said it was a while ago....
it most likely was a T3 gt35.

-J

 

Woe is my because that is what I have. But wait, my exhaust AR is 1.06.
OK, I am happy now.

 

It's ok Chuck.......you gotz dat mad power in y0 ride t3 or not!!!!!!!


-J

 

That's just it, there was nothing limiting it. Large M2/ASP IC and Cold air intake, good fuel system, open exhaust, Twin power ignition, solid compression numbers, good tune. That is all it put out. Same setup here put out over 400 numerous times.

Motor was built by roger mandeville, look him up on google. There was no reason the car shouldn't have put out more power. And with no noticeable reason the customer didn't feel like paying us or anyone else to tear it down. The car was solid very well put together, just made low power.

 

I'm guessing he had the engine rebuilt at the same time of going single. If he swapped his twins back on he probably would make 50 less then he did before with those as well. Making power is really quite simple. Get more air into and out of the engine. I don't think it can be argued that a gt35 handles getting more air into and out of the engine better then the stock twins. So if nothing was wrong with the turbo it must be something with the build. Maybe the builder welded the secondary ports closed haha. I guess it will just have to go into the unsolved mystery case

 

If the motor was put together by some of the "engine builders" on here I would agree, and no one is perfect, but few people if any know more about rotaries better than his builder did. I agree, and it went in the unsolved mysteries bin.

 

Well also he's making that power at 14psi which correct me if I'm wrong but most people with gt35r's that are getting 400+hp are running more boost than that.

 

We need more info from the OP... we can debate setups and give scenarios for this turbo and that turbo all day long.
What specific setups is the OP looking to compare?? Stock twins vs. small single... stock twins vs. large frame turbo? What about twin GT42's vs a t3/4??
If the OP is just asking for theoretical info of "X single turbo" vs "Y twin turbos", his question has been answered, and again, it widely depends on the setup. There really isn't any cut and dry answer.
If the OP wants a much more precise answer, they need to specify the intended setup of interest.

 

Yes there is.... Compressor size/CFM.


-J

 

 

 

In saying there is no cut and cry answer I was referring to the set up, given the OP's original question...."Would 14psi on single turbo make more hp than 14psi on twin turbo?"


Example 1:

14 psi through a SINGLE Toyota CT-26 on a free flowing 7MGTE motor: 312 rwhp
14 psi through a TWIN GT30 setup on a free flowing 7MGTE motor: 510 rwhp

For this scenario, the answer for the OP's question would be "no."


Example 2:

14 psi through stock TWINS on a 13B with supporting mods: 355 rwhp
14 psi through a SINGLE GT42 on a 13B with supporting mods: 450 rwhp

For this scenario, the answer to the OP's question would be "yes."

So, we really can not give him a yes or no answer... it all depends on the setup as illustrated above, hence my saying there's no cut and dry answer. Hope that clears it up a little.


But yes, CFM alone, the greater the number... the greater the potential. To illustrate that, an intake manifold we built for a 3.0 litre supra made 35 additional rwhp over the stock intake manifold at the same 13 psi. The only difference being the fabricated manifold flowed around 30% more CFM per runner.
Same psi... different CFM. Simple as that.