Turbo discussion FP black VS Greddy 20g
 

Alright guys so I finally got my car back on the Dyno after installing the FP black turbos. Now my first impression for the butt Dyno was that the turbos made a pretty big difference. Last time on a mustang dyno with the 20g's my car made 527Whp and 554wtq @16 lbs of boost. After installing the turbos I didn't have to change the tune much. I made some slight changes to the fuel map. So I added more boost. I bumped it up to 20psi. First pull on the same Dyno at 20psi was 520whp and 602wtq....? I was a little upset beings I had just dumped 2k into the FP black turbos. So I added a degree of timing and final numbers were 572whp and 571wtq. I'm tuning on pump93 and VP110 mix. Why did I gain no power from turning the boost up? Only torque. I was expecting to see around a 80whp gain from the boost increase alone. Input would be great guys.

Turbos are out of air at higher rpms and boost or exhaust backpressure is too high. Either one and high rpm torque will fall off. I think the compressor wheels have more in them, so I'd look for an exhaust restriction... (I've seen 18Gs make 700)

youre engine works as a package. Air in, air out. Any other restrictions? Headwork?

For reference, i made 634whp/590tq at 20psi(21psi peak towards redline as we added boost to counteract the DE drop) on a stingy SOHO dyno, made 640whp/580tq on 18.5psi on the Z1 dyno. My guess is if I tuned for 21psi all across the RPM and dyno'd at Z1 it would be 700whp/640tq. Meth helps too.

efficiency island!!!!

boost does not equal air flow
airflow equals horsepower

infact, boost (past a point) is bad ... it represents wasted energy, wasted air flow, and added heat (this is compliments of TCode btw)

did FP give you a compressor map for your new blowers? Figure out where your max airflow and max efficiency is and tune to that.

get rid of as much back pressure as you can and do whatever you can to cool your intake charge ... insulate your intake ducts, add meth, dont pull intake air from behind your radiator!

I don't think it's a compressor / intake side issue or a turbine issue. Greddy 20Gs should easily get into the 700s at those boost levels on these motors. It's got to be an exhaust side restriction. Muffler, cats, or small piping.

The fp blacks didn't come with a compressor map. But they supposedly flow 71 lbs per minute each vs 41 lbs per minute with the 20g's. I was expecting around 100whp with added flow and boost and having to change the tune. But obviously that didn't happen. I will be switching the car to E85 probably next season or later this season and adding boost again I'm not messing with meth injection it's just another thing to fail. The exhaust is straight dual 2.5" from the turbos all the way back to the muffler I don't see that being a restriction. And the intake manifold is a Crawford upper plenum with ported lower plenum and runners. But the heads are stock. I'm sure head porting and 1mm oversized valves would help with flow but I probably won't take the car that far that stuff is expensive. I ordered some Hoosier stiff wall slicks and thinking about buying the import drag solutions rear drag suspension kit. I need to make the car work before I add anymore power. I have logs of it spinning at over 100mph on the street tires.

I highly doubt a muffler would cause enough restriction especially an aftermarket muffler. But only way to find out would be to add a back pressure sensor and I'm not digging that far into it. And I really don't want the car to be obnoxiously loud out of boost. I like the sleeper effect cause wastegates vent to atmosphere so it gets pretty loud when they open. It's not super quiet but manageable out of boost. I took the cat back off and started the car with just down pipes and it was ridiculously obnoxious.

Could add some boost activated cut outs?

I'm not calling anyone a liar but the proof is in your dyno ... something is going on. What are your intake air temps? Is your timing dialed back due to hot IATs?


Yea - dusting off Corky's book - page 133 on exhaust systems puts 2.5" duals in the 900bhp range.

do a few pulls with no muffler!!

could be (but prob not?) suspect - you cant modify 2 out of the 3 and expect proportional gains. my gutted upper & lower helped hp but killed my torque. I subsequently went back to a DE unmolested plenum.

not a fan of cutouts ... sounds horrible!

71lb a minute.....they should have a compressor map to show this.


My guess it is a PEAK number under the best conditions to make the turbos sound good.
Similar size turbo housing, you think they can just about double the flow rate at the same PSI?

These turbos are meant for evos, small high reving shitbox cars. They are meant to run much higher PSI, 18 being the minimum recommended.

Numbers aren't everything.

When I got my Z tuned I was sitting next to a kid who had a 540whp drag built k series civic coupe. We were talking about exactly this. His first dyno he only got 540whp but set a like 9 second time at the track.

He went to another shop and got a retune and they got him all the way to 670whp. He was stoked and went back to the track and lost almost a full second. Tho his numbers were higher his times and actual speed output was much slower.

This time he came back to the shop who had the lower number tune but gave him a better time slip for a new tune. How well and clean the tune is, is much more important than the actual number output.

That's why my first couple pulls made 410ish and after cleaning the tune up they went down to 385 wheel before they were done. And I've raced and beat 450whp super charged 370's... So don't stress the numbers more than the results.

Ok...so i may catch hell for this but i am gonna say it...the 370z guys sit there (just like hr guys) and hang their hats on the WHP numbers. They often exclude their tq numbers....well because their dyno is like a honda 4cyl. They carry what little torque they make deeper into the RPM's which gives them HP. They love to brag about their 600whp, 499wtq stock block builds like they are god's chariot. They rev a few rpm higher than my little DE. Yet at the same whp, ill make 100 more wtq.....now with all that said it takes me 20psi vs their 12-13.

So beating a supercharged 370 which was probably 340wtq is nothing to brag about.

Yeah a tune matters and if you cant put the power down you are gonna have a horrible ET with a great trap.

Again, my guess is the 71lb a min is a peak value that you are now where in range of.

preach it!

Just unbolt the muffer for the dyno test. You don't even have to remove it. I lost close to 200 whp adding a muffler and got 99% back with boost based cuts outs that route around the muffler at WOT.

Iat's were definitely high and we made 3 consecutive pulls on the Dyno. They were having issues with room calibration. I had the engine fans running on the Dyno and they pull air off the radiator which will be fixed later this season I'm going to make some new air intake pipes for the turbos. I may also do the boost activated cut outs and see if it makes a difference or build a whole new exhaust setup completely. Here's a pic of the Dyno graph for reference. Had a misfire toward the end of the pull which I'm guessing was detonation caused by the high iat's. The car feels fast boost comes in hard and keeps on pulling. But your right numbers don't mean everything I raced a 700+hp turbo LS 4L80e fox body and was on his bumper at 140mph. And that car was at least 500lbs lighter cause I had a passenger and his weighed in at 3050lbs.

exhaust cut outs for the win!
 

I've not posted this in my build thread, but my graph looked like yours up top when I added a muffler; torque fell off in high rpms. Put on exhaust cut outs, and flattened out the torque curve up top. This is with a modified G37 muffler and 4 cats on there, 100 cell and 200 cell in series! See attached.

Are you using the greddy filter-to-turbo pipes?

whats the harm in a very conservative water methanol setup but tune without it...

Once again it's just one more thing to go wrong. I have a nitrous setup on the car but haven't used it yet. I was going to spray a 35hp dry shot to bring iats down but the tuner wasn't comfortable with it so I have yet to even fill the bottle. But I'd rather just switch the car over to E85 and not have to deal with water/meth.