FDNewbie

iTrader: (10)

LOL...holy..... That's a HUGE difference.

RotorMotor

iTrader: (5)

wow that looks MUCH better than the cosmo stock one . oh and as far as the questions about pettits conversion... im pretty sure the turbos are run *non-seq* (even though they say they are seq). i believe it would be possible to use almost any computer with enough outputs to control the various seq. solenoids if you were trying to have sequential... it would just be a pain in the butt to set it up properly. im not sure what the other 20b guys do about airflow sensing when they use aftermarket ECU's... i havent crossed that bridge yet.

jimlab

Considering that Pettit uses an Electromotive system for engine management (unless something has changed) I'd say it's a safe bet that the 20B twins are *not* running sequentially.

FDNewbie

iTrader: (10)

Jim, I'm sure you saw this in David Hayes' post...(I asked SPECIFICALLY because I've gotten yes' and no's about Pettit running sequential twins...)

jimlab

Personally, I don't think he knows all that much about the conversion. He also repeated "375 RWHP @ 6-7 psi".

jimlab

Did you read my post on the last page where I said "unless something has changed"? Pettit used Electromotive engine management in the past. If they're using something different that will allow sequential operation of the turbos, great. It still won't make 375 RWHP @ 6 psi...

jimlab

Cool... I knew something was wrong with the forum when the last post I made couldn't be edited immediately after I made it. According to the forum's "clock", at least where I'm concerned, it's 1 hour behind the actual time. I will be making this post at 12:12 pm and it will show up as having been posted at 11:12 pm, earlier in the thread. Cool.

RotorMotor

iTrader: (5)

DP

RotorMotor

iTrader: (5)

we are digressing from the purpose of this thread. but as long as we are, i must state that i agree with jim. in stock form the 20b twins are reported to run out of flow as you increase RPM.... meaning that at first you see 10PSI, then as rev's increase it steadily drops to 6PSI. this is partly due to splitting 3 exhaust pulses into 2 turbos, and having all the hardware (flapper doors) in there to redirect oen of the pulses to one turbo and the other two to the other for the 2nd seq stage. needless to say it is far from efficiant. it is also my understanding that pettit does nothing more to the turbos than take them apart, smooth out a few bends, ceramic coat them and put them back together. so the question is where are they getting all this extra efficiancy in the twins from? well if you remove all the flapper doors for seq. and port them even further you will free up a good amount of flow. also i dont know how they would be able to use a sequential setup with the computer they are currently using. if i were to put two and two together i would have to say they that pettit runs them in parallel.

RotorMotor

iTrader: (5)

bahhhh my posts are going to the MIDDLE of the page... i hate the new forum.... the last version was slow but this one is slow AND retarded. sorry back to the thread

clayne

He might have been talking 20B or something.

FDNewbie

iTrader: (10)

Clayne, he is talking about a 20B. He's getting the Pettit Banzai conversion done to his car

Jim, you may very well be right, but I would think/hope that when he was discussing turbo options w/ Pettit, they made it clear to him whether it was sequential or parallel, and that's why he told me they're running them sequentially.

Also, see this:

FDNewbie

iTrader: (10)

Jim, I'm not trying to proove you wrong. I did see your previous post. I'm just gathering all the info I've found to try and see what's really going on. I'm sure he ran the Electromotive in the past, and I guess now it's Link ECU (both of which I haven't heard of). And I'm not even going to dispute or make any claim about any hp #s they make at any boost. I'm just trying to find out for sure if they're running sequential twins that actually make 550 @ the flywheel. If so, given Cam's "margin of safety/reliability," I'd think the twins can actually break 500rwhp.

I think I'm gonna make a few calls tomarrow and see if I can find out for sure...no more guesswork.

RotorMotor

iTrader: (5)

pass 500HP you say? HA! thats a stretch... especially in sequential! i dont know, maybe it can be done but they really dont flow well. i was debating sending my set to BNR so they could work their magic on them. if the cartriges can be replaced with ball bearing ones, then maybe its worth it, but frankly for high HP cars a single is more cost effective. even better would be 3 small singles though.... anyway we better stop talking about 20bs and start talking about MAF sensors before this thread gets bumped to the 20b section hehe

clayne

370 on 7 psi is very doable with 20b.

Look at Red-Rx7's or (whatever his name is) car.

jimlab

A stock 20B uses a MAF sensor. I think you'll find that Pettit's conversion (let alone any 20B conversion I've ever heard of) does not...

jimlab

So an engine that made 300-320 horsepower (flywheel) @ 10 psi stock suddenly makes 370 with less boost, not to mention 375 at the rear wheels @ 6 psi? Come on...

I'd like to see some proof. Someone show me a picture of a 20B conversion with the Cosmo twins and a dyno sheet for 6-7 psi for the same car, if you can.

FDNewbie

iTrader: (10)

That, along w/ David Hayes' quote earlier, saying that Cam rebuilds them, including new cartridges, smoothing out the surfaces, blueprinting, and ceramic coating them...tells me that hey, maybe they can make some significant power (def. not "stock" cosmo twins).

Oh and RotorMotor, I believe this 20B stuff is crucial to the MAF discussion. Why? Because if Pettit is actually running the 20B w/ sequentials, that means we have an excellent candidate for an EMS, since the 20B utilizes an MAF as it is. The only diff. I'd see would be getting it to run 2 rotors instead of 3. I'd think that's a hella lot easier than trying to get an EMS (like AEM) to run the sequentials...right?

PS...what on EARTH is goin on w/ the forum??

FDNewbie

iTrader: (10)

RotorMotor, plz keep me updated if you do decide to see what BNR can do w/ the twins.

Oh and breaking 500 came from the assumption that 550 flywheel is in fact w/ sequential twins, and that should be something around 480 to the wheels. 20 more hp seems very reasonable if you up the boost a bit. Again, this is keeping in mind that Cam is conservative in his tuning, because he's more about reliability than max hp #s.

Jim, see, I assumed (which was wrong of me) that if you start w/ a MAF, you're gonna continue w/ it. You're saying that Pettit prob switches from an MAF to a SD system?! Why??!! If you have something good, don't you want to build upon it, not take a step backward?

jimlab

550 flywheel horsepower is apparently at 12+ psi, so you're already pushing the Cosmo twins at that level. Still, I've yet to see a dyno curve for a Banzai that wasn't created in Excel.

Because they're not using the stock Cosmo ECU and engine management systems that will control a 3-rotor and use a MAF sensor don't just grow on trees.

Speed density is not necessarily a "step backward". I've already listed a few examples of where it's actually beneficial.

ZoomZoom

iTrader: (2)

I am definatly interested in this, I had asked the question but it was squashed years ago. I knew the MAF had some benefit and it didnt seem to make sense. But the guy seemed to know more then I.
Also the old 5.0 mustangs used to use Speed Density and then gained power with the MAP system that became standard in the late 80's, it was also needed for the aftermarket Supercharger kits of the time. So if you had a previous year prior to MAF you had to buy the parts to convert your Mustang.

jimlab

You are aware that Red-Rx7 has a 1.32 A/R T-76, right? We're talking about the Cosmo twins, that Cam apparently said made 375 RWHP @ 6 psi.

su_maverick

so, is anyone going to try this out or is it just speculative fun?

RotorMotor

iTrader: (5)

well jim i do agree with you that pettit may eb exagerating (and the 20b is not some magical engine... although i do think its cool ) anyway, as much as i think they are exagerating there is some evidence to warrant their claim. pettit ports their engines and also uses larger than stock intake tubing. so now that we have increased the volume of air that the engine can process at any one moment (compared to a stock 20b setup), we can think about pressure and volume. lets take a pressure reading before the TB on pettits engine and a stock one (keep in mind hte former engine has larger intake tubing and a huge intercooler compared to the stock setup). if we were to generate the exact same flow from a turbo on each engine, we should notice a pressure drop on pettits engine (compared to the stock one) as the volume of intake tubing is larger, and it can process more air because of the increased ports. therefore it sounds plausable that even if you are seeing only 7PSI on pettits setup, it verywell may be flowing just as much (if not more) air than the stock one.... i guess we would need some sort of mass air flow sensor somewhere in the intake piping to be able to tell how much air is actually flowing through each engine ... see i tied it back in with the original purpose of this thread hehe. as far as this thread is concerned, the MAF sensor will be the most accurate, but im almost positive that pettit throws it in the trash and uses a SD system. thats how all the 20b guys do it (unless they are using the stock ecu... which can be done). -heath

su_maverick

Well, we have all seen the cone-type MAF that the 20b has and I would want the SD over that but I think FD and I were talking about something like a hotwire type MAF that wouldnt have that type of restriction.
Neal