I think its just a matter of the turbos not being able to meet the demand of the engine. At high rpm's its ability to take in air excedes the turbo's ability to feed it compressed air, so as a result the air pressure goes down.

On a completely different subject, I spoke with one of the guy's at Pettit today (I was calling about subframe, but I asked lots of questions about lots of stuff while I was on the phone) and he said that the Banzai setup uses the stock turbos. They do port out the exhaust manifold, remove all the sequential doors, etc, and enlarge the turbine housing, but the wheels and all aspects of the compressors remain completely the same. They were making 412 (I think it was 412) at the wheels very recently at around 14 - 15psi.

This is very interesting to me, as it implies that perhaps the compressors actually can do a better job of keeping up with the demands of the engine, its just that the undersized turbine housings cause them to overspin and thus go out of their efficency range. If this is the case, and pretty much anyone can take the turbos apart and do what Pettit did for cheap (though obviously you'll have to send the turbine housings out somewhere, that's not exactly Dremel material...)

 

I have only been posting that for the last two years now.

However, I am glad that you called Pettit, rather than listening to the internet peanut gallery.

 

Well, its just that a bunch of people have been saying a bunch of different things, so I figured I'd just find out myself.

For example, a lot of people have been saying that Pettit is now using Hinson Super Car's adjustable arm method for bump steer correction, but they are not, they're now using adjustable spindles. In addition, the ONLY significant chance between their old 20B subframe and their new one is that they make the new unit completely from scratch. Other then that, the fitment, placement of steering rack, etc, is almost exactly the same.

Honestly though, after talking to Pettit I'm starting to feel iffy about going with a single during the initial swap. If porting the manifold / turbine housing really makes that much of a difference, then that's a great way to save $2500. However, there are still some definet advantages to running a single, as I posted above, so like most things, it just going to come down to how much money I'm willing to spend once I get everything else I need first. And yes, I do realize that you've been saying this for quite some time, Evil

 

Exactly. The internet is a great source of both information and misinformation.

"Trust, but verify." - Ronaldus Magnus

 

well i should start up somewhere next week if all goes well ,i`ll let you guys know

 

how do you consider the turbos to be stock w/ so much work done to the hot side? if you open up a stock motor and bridgeport it, it will definitely not be a stock motor, even though it uses stock components.

 

The ONLY modification to the turbo's themselves is the porting of the turbine housing.

The manifold is cleaned up (all the sequential hardware is removed), but other then that, the entire system is pretty much stock. Does it make a big difference? Sure, but its not a major change, and pretty close to a true non-sequential conversion on the stock 13brew turbos.

Its all a matter of terminology, though. One man's stock turbos are another man's BNR stage 3. The way I see it, if you have the stock wheels and housing (regardless of porting), they're stock-enough.

 

yeah speaking of the BNR's, thats another option for the stockers as well... they can do a bunch of stuff to them

 

Yeah, but they way I see it for the price it just makes more sense to go with a single, for the reasons I listed earlier in this thread. However, it all comes down to what sort of power you want to make, where you want to make it and how you want to make it.

 

It was generally known that Pettit uses the stock turbos. As confirmed here, he modifies the stock turbos to get more HP out of them.

 

ahhhh, modified turbos are not stock turbos. no one would refer to a modified fd as stock.

 

i would still prefer single turbo less hassle ,less underhood clutter , more power , less under hood temps , better exhaust flow (depending on header construction), plus ...IMO looks better than the twins...has that " ...oooohh shiiiit" effect
i would say its a fair trade off for lag

 

Why would anyone waist thier time and gobs of money doing a 20b conversion to run the stock turbos that max out at 400rw? You can do that with a 13b. If I had the money for a 20B I'd run a T72 with it and make around 600rw on pump gas.

STEPHEN

 

I agree with you stephen, but I would use a T76

 

One of the many times I was at Pettit before they moved Cam showed me a set of 20b turbos that were modified by using the the stock FC's HT-16 compressor wheels in both the primary and secondary turbos.

 

For me at least, the 20b isn't about peak power at all, its about the area under the curve. You can make plenty of power with a 13b to get you going VERY fast in a straight line, but for a super broad powerband three rotors are the way to go.

Besides, even though a single turbo setup may not be that much compared to the rest of the cost of the swap, its still at least $2,000 when all is said and done, and $2,000 is still a lot of money. My goal for now is just to get everything up and running.

 

i can speak for me, i wanted to get it running and not have to worry about setting it up or finding the right turbo. its a big enough job where anything you can do to make it simple helps.

 

It's always fun to add more fuel to the fire....
My car is 99% done. It went to the dyno for final tuning yesterday. I was unable to be there due to prior commitments, so I don't have any of the charts, etc I am relaying the information so I will be able to answer limited questions.
RWHP = 350
Torque = 278
At what RPMs = I forgot to ask
Peak Boost 13 PSI up to 5k trailing off to about 10 PSI past 7K
What were we running:
To all of you that said it couldn't be done, here we go:
20B (B series motor) rebuilt by Pineapple Racing with new 3rd Gen housings, small street port, oil mods, and ceramic apex seals. Stock computer with rev limiter, boost limiter and speed limiter removed. Stock injectors, stock turbos (rebuilt to stock specs) running sequentially.
I was there last week and all I can say it that it is crazy fast and it sounds AMAZING!!!

 

congrats! hatley-san told me this morning

 

Is this the old Mariah 10AE?

Nice numbers!


-Ted

 

Yes, but the only thing that is really "left" from the Mariah car is the body kit. The set-up is completely different. I'll post some before and after pictures later.