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I had an impulse buy and splashed out on a new turbo, it was on clearance at the local store and picked it up for a great price, from my limited (and to be honest slightly rushed) research it seemed to be suitable but wanted to check with you guys on what you thought.
I realize likely all the information I need is somewhere here on the forumn but thought it would be easier to get some up-front feedback from you guys.
Here is my current setup:
13b Full Bridgeport
big injectors
Microtech LT-10s
Flowed s4 Turbo (9 psi)
Turbosmart Ultragate 38mm External gate
Big intercooler
Power: 280HP@wheels freshly dyno tuned
I just splashed out on a turbo at the local dealer (was at a clearance $$rate) and did do some research prior however I would like to check if I got the right one for me and if it will work fine for my application.
I am able to return it if its not "perfect" but moreover I want to make sure its suitable for a rotary engine and can do the job.
What I am wanting:
good spool up 3-4k rpm, good/more power, street friendly
Here is what I purchased:
Borg Warner s300sx - Model: #177281 Compressor
Wheel inducer 66mm
Compressor outlet 3.00
Compressor inlet 4.00 Turbine Exducer 73mmTurbine outlet 4.00 V-band
Housing T4 open flow .88 A/R
AND...Turbosmart Pro-gate lite 50mm v-band Wastegate (with 14 psi spring)I will be having it dyno tuned again immediately after of course.
Look forward to hear your feed back, did I waste my time? should I take it back? should it do the job?
If he was running an s5 turbo then the new turbo is definitely going to be a different animal. I would have almost said the compressor is maybe one size bigger than necessary if its the SXE version and continuing to run low or moderately low boost. He may not want or need 600hp.
For higher boost might want a bigger T-housing.
Its definitely going to be better than before anyway.
Currently I am running 1000cc injectors on primary and secondary.
Do you guys think this is enough for 14 psi on my setup?
Probably a bit shy even for 14psi considering big efficient compressor and bridgeport.
Best way is to calculate fuel requirement from the lb/m rating of your compressor.
Dont ask me to do the math right now, but check Howard Coleman's stickey at the top of this section.
Mass air flow of turbo dictates how much injector you need at say 10:1 air/fuel, and then you need fuel pump that can supply that.
To be safe you really want more injector than turbo, and more fuel pump than injector.
given your interest in "3 to 4000" spool you are facing a headwind with the bridgeports. bridgeports trade early power for later power due to a much greater overlap.
this is not life threatening but is a significant factor achieving something meaningful at lower (3 to 4 K) RPMs.
as has been mentioned above the 66 is a couple of clicks above a perfect match for your stated objectives. the combo of the bridgeports and a harder to spool turbo will generate a real push around 7000 or so but be a drag below.
the turbo itself is a curious combo in that it has a really small hotside housing combined w a large cold side which combined w a rotary is a recipe for lots of exhaust backpressure which then gets swept in to the next intake stroke especially due to the bridgeport overlap. (overlap being tha amount of time the exhaust and intakes are both open).
if you can do it, i suggest you trade it in for a 177280 or 177283 both with a 177209 hotside.
less backpressure and a better match for your objectives.
you were very correct to lose the 38 mm wastgate. a 38 has 1.76 sq inches of piston area. the 50 has 3.04 sq inches, up 73%. depending on your manifold and a few other considerations the 50 might still be a bit small for the 66. i run a single 60 on an ultra flow manifold. the 60 has a 4.38 sq inch area up 44% from the 50. if you are buying a large single WG i sure would go w the 60.
as to fuel... 4 1000s on gas...
4000 X max duty 85% = 3400 minus lag at 13% = 2958 CC per minute net (into the engine)
2958 CC/min to gallons per minute = .78 GPM X 6.35 (weight of gas/gallon) = 4.953 pounds per minute.
4.953 X 10 = 49.5 pounds of air per minute at 10.0 AFR.
49.5 X 14.471 = 716 CFM of air / 1.92 = 373 maximum rw rotary hp (SAE) at 10.0 AFR
sure, you will run around 10% leaner but there are other small deducts so you want to be conservative w fuel.
you currently have a 66 turbo that can do 69 pounds of air at 14.7 psi and 79 pounds at 39 psi.
you will way run out of fuel even at one bar of boost w the 66.
proper fuel to air matching should assume enough to match the turbo's max air output as sticking wastgates can prompt a call to your engine builder.... always more expensive than larger injectors.
you have a significant amount of mismatches and i suggest you get everything better aligned before firing it up.
also, i didn't see any mention of an AI system.
the rotary is a small displacement engine that breathes like a really large engine and as such can make big power but has high combustion chamber pressure and heat. everything on the rotary has to be just right... there is a small window where things work and a large window where they don't. fortunately we have the internet and this has all been done successfully before so it is just a question of doing the research.
given your interest in "3 to 4000" spool you are facing a headwind with the bridgeports. bridgeports trade early power for later power due to a much greater overlap
Howard
Be careful, you might make some heads explode speaking that way in this community. Bridgeport fan boys gonna lose their minds. "But listen to that Brap Brap bro"
I'll say it in less words than Howard. You bought the slowest spooling 66-67 mm turbo on the market. You say you got a great deal but you can find them all day for $575-600.00. It's s cheap reliable turbo. Not the best response, not the best top end. Just a cheap reliable turbo.
Be careful, you might make some heads explode speaking that way in this community. Bridgeport fan boys gonna lose their minds. "But listen to that Brap Brap bro"
I'll say it in less words than Howard. You bought the slowest spooling 66-67 mm turbo on the market. You say you got a great deal but you can find them all day for $575-600.00. It's s cheap reliable turbo. Not the best response, not the best top end. Just a cheap reliable turbo.
Be careful, you might make some heads explode speaking that way in this community. Bridgeport fan boys gonna lose their minds. "But listen to that Brap Brap bro"
I'll say it in less words than Howard. You bought the slowest spooling 66-67 mm turbo on the market. You say you got a great deal but you can find them all day for $575-600.00. It's s cheap reliable turbo. Not the best response, not the best top end. Just a cheap reliable turbo.
I am going for bigger injectors and then a tune. I am really curious to see how it goes now.
Howard, I am going for x2 bosh 1600cc which will take me to 5200cc gross.
Pheww, I thought it was too small because everyone seems to be using the .91 AR
A/R is the area/radius of the housing and while certainly this affects boost response vs top end flow/backpressure..... when looking at the size of a turbo both wheel (compressor/turbine) measurements are typically what you want to look at. You're running a 66mm compressor inducer coupled to a nice big turbine wheel.
I think if just running 1 bar boost like you say, the turbo will be ok, just has a bigger compressor than needed, the small t-housing will help compensate with spool up at the cost of some top-end power.
If you want to safeguard against boost spike lean-out on that turbo might want 2000cc secondaries (no math done tho )
As noted, ideally for your 14-15psi goals, the 62mm version with a 1.00 or larger t-housing would be better if its possible to swap over.
As mentioned - it will be laggy, but should do the job. Just have to weigh up the cost of a tune v another turbo if it turns out you dont like it.
I think if just running 1 bar boost like you say, the turbo will be ok, just has a bigger compressor than needed, the small t-housing will help compensate with spool up at the cost of some top-end power.
If you want to safeguard against boost spike lean-out on that turbo might want 2000cc secondaries (no math done tho )
As noted, ideally for your 14-15psi goals, the 62mm version with a 1.00 or larger t-housing would be better if its possible to swap over.
As mentioned - it will be laggy, but should do the job. Just have to weigh up the cost of a tune v another turbo if it turns out you dont like it.
Hi,
That sounds like a reasonable compromise, I have also purchased a new Bosch 044 Pump as there was only a cheap chinese type installed feeding the rail so got this for extra security. (rated for 700HP)
The injectors I have purchased are actually 1650cc Bosch so gross will be 5300cc and with a Bosch 044 and a Holly Blue feeding the surge tank....from what I have read/asked multiple people this should be perfect for what I am doing.
Now just to get the tune and see how she pulls up. Will post dyno results/video once its done.
It will be ok as long as you dont overboost. Your inj/pump combo is a good match but turbo is capable of leaning that out .(700 flywheel horse piston engine, more like 400rwh rotary)
given your interest in "3 to 4000" spool you are facing a headwind with the bridgeports. bridgeports trade early power for later power due to a much greater overlap.
Is this always the case with the normal bridgeports? I am a bit lost in my reasoning because in piston engine world everyone is using overlap to increase spool.
I am just comparing now simple PFI engine with only VVT on the intake cam.
I did a few of these motor for serial calibration and in spool area (thesedays 1250-1750 rpm) its not unseen to gain 20-30% torque with 20-30 grank degree advanced intake cam.
advanced intake cam is just what quick opening bridgeport does, opens the intake valve/port when exhaust isnt closed yet.
Quote:
Originally Posted by Howard Coleman CPR View Post
given your interest in "3 to 4000" spool you are facing a headwind with the bridgeports. bridgeports trade early power for later power due to a much greater overlap.
Is this always the case with the normal bridgeports? I am a bit lost in my reasoning because in piston engine world everyone is using overlap to increase spool.
That is their opinion which I think is wrong.
The factors clouding the issue are that when people do bridge ports they are usually for racing and also trying to raise the high rpm torque (for more torque at the wheels with gearing multiplication).
This means they almost always increase the port duration (later closing) as well as the earlier opening timing. Later closing will hurt intake velocity from compression stroke reversion back into the intake at low rpm.
They almost always increase the port area. Add a bridge. That slows down intake velocity at low rpm as well. If one wanted to maximize low end and midrange with a bridge port one would fill in the stock port to maintain velocity.
Even with these disadvantages we can see this half bridge EFR 8374 makes at least as much torque at 3,000rpm as the best stock port EFR 8374 or best street port EFR 8374 (compare Dynojet to Dynojet charts because they have fixed inertia/consistent load for spool).
Imagine if the bridge port was set-up for low rpm/midrange power.
i am not too concerned about the turbo making power and BTW, that is a nice looking sheet
i am concerned that the hot and cold sides are mismatched w the really small .88 A/R on driving an 80 pound cold side. hello backpressure.
i also don't like the non divided feature.
being not divided and small plays the wrong way w a rotary.
i suggest you swap the hotside for a 177905 1.0 divided.
Ok so heres what happened. Engine was recently rebuilt by PPRE in NZ (the guys responsible for Mad mikes quad rotor and the worlds first 6-rotor engine) Studded block, PPRE seals, new porting etc etc.
Car is now nicely tuned at 270KW atw on 14psi (on a very conservative reading dyno I have been told) so likely closer to 285KW
Here are a few points I would like to make about my setup noting turbo choice and fueling:
1) The turbo was nowhere near as laggy as some of you made it out to be!, it spools quickly and has excellent response right from the get go! totally contradicting almost everything said here about my setup! however tuning and engine build works together as a package.
2) 5300cc NET was more than enough fuel. The tuner (who knows what he is talking about, i.e tunes rotors all day everyday) said I would have been fine with my 1000cc injectors (4000cc net) and the fueling upgrade was not necessary for my setup.
So there you have it, super happy with my setup. Love driving it - very fun! and very quick.
If anyone is planning on running a similar setup, please pass on my experience or I am happy to answer any questions.
12-30-16, 02:52 PM
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