Gt2871 dyno
 

Attachment 195721

Build details in sig. Whatcha think? Keep in mind that this is a dyno dynamics dyno. They said that it generally reads 17% lower than a dynojet.



EDIT: 95, MSPNP, 1.9L 99 head, 550's, 949 racing twin disc, 6-spd, gt2871, 9:1 Wiseco's, M-Tuned Rods, ARP Head and Main Studs, ACL Bearings, BE OPG'S, ATI Super Damper, HDHTDCDD, DO WI

How much boost?

I like it. Allot. Definitely time for an intake manifold though.

seems to spool up a little slow for a 2871, what manifold?

17psi maxing out my 550's

niice

Begi cast mani

I've been out of the game for a while. What's the best option for an intake mani nowadays?

modified honda mani.
or one of the members (psi somthing) makes them now.
or make your own


You need bigger injectors too. ID1000's or DW800's would be great

man I would love to go for a ride in a Miata that makes 250+whp...congrats man, build looks tasty.

Looks good but needs absurd flow and an intake mani.
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more like 12-15% low unless their correction numbers are jacked...which they probably are.

Gotpsi intake mani and better exhaust mani

do you have a fuel pump?

Yes. Walbro 255

What is your exhaust? I spooled dick when I had stock exhuast.

And were you running WI?

I have a 3 inch exhaust with a flowmaster chambered muffler. Devils own water injection

Get rid of that flowmaster and get something with a straight through design. Those chambers are horrible for flow

K, now I get to make fun of you. Get that POS muffler off the car and replace it with a big Magnaflow. Something you can literally roll a tennis ball through, please. There's no excuse for torque that doesn't peak until 5200rpm like that - you should be able to move that entire chart down 700rpm with just a muffler change.

Also, find a dyno operator that knows what he's doing. Starting pulls at 3500rpm = :jerkit:

Fix those two items and you should be able to see full torque in the ~4000rpm area, especially if that's a .64 A/R 2871R. Regardless of what the actual torque numbers are, just the torque line vs. RPM is pretty poor, and I bet it's all due to muffler and dyno operator error.

I have seen big horsepower cars use the Edelbrock Super Victor.

Did you fuck with the timing at all?

I haven't looked at too many 2871 dynos, but it seemed like it took a while to spool then once it got there, it dropped off. It looked as if the turbo was too big for the engine, but without the peak numbers, which would indicate a lack of flow.

It sounds like the first thing to do will be to get your exhaust flowing better, then maybe an intake manifold followed by larger valves

I dont know if this is my best plot, but this is my set up. 1.8 built. BEGI cast mani. +1mm valves, 3" DP and exhaust.
This is about 1.5yrs old. I also have a gutted 99 intake. Thats not helping my spool.
gt2871r.

My point is, I believe you can do better. Esp with it being a 1.9??

Dynos make what they make. Any dyno operator can fuck with the numbers as he pleases and one of them leave their baseline as is. I've been on dynojets that are spot on with a fairly close drivetrain loss estimate and I've seen Mustang dynos that were jacked up from their "heartbreaker" numbers.

You get a baseline, you get it tuned, you get a final number, you compare the difference. That's what dynos are for.

I'd much rather have a dyno operator that knows what the fuck he's doing than some moron on the "most accurate dyno in the world".

And BTW, any good tuner knows the tuning differences from Dynojets that most owners don't set up for load (though they can), and a street tune. If you think you need a load bearing dyno to properly tune a car you really need more tuning time to know what the hell you're doing.

gj wes

BEGI cast mani is ambiguous, but I'm assuming you mean the turbo/exhaust manifold. I'm not super experienced with this stuff, but your torque curve doesn't look too much better than his. Torque (minus velocity-based losses) is directly related to acceleration, so a flat torque curve will yield a nice, smooth "close-to-constant" acceleration. I don't imagine that weird mountain looking thing going on in there is very smooth to drive.

I think a good intake manifold like the honda skunk w/ BP flange welded on, should prevent the torque curve from going limp like that without taking away too much low/mid-range.

Damn guys quit gangbanging the frikken intake manifold wagon. There are lots of 350+ hp miatas out there with stock intake manis.

There's lots of other shit in the car that affects the numbers not to mention the frikken tune, the damn boost control system, heatsoak etc...

You know for all the cheering about intakes I haven't seen -one- real back to back same day pull with the ONLY change being the intake swap out.

Show us ALL THE examples.
If he's holding a pre-set pressure level all the way to redline what the fuck else would you IMPROVE on in the boost control system?

There are many here that have shown before and after dyno sheets. The numbers don't lie.

If you're going to go against the majority of members on here in your way of thought you better provide some damn good examples to validate your reasoning.

So far only thing you've shown is how badly someone could fuck up a frame rail with a hack saw.

Not the same day, but the same dyno. Only other change is VVT, but I have another dyno graph proving that doesn't make more than 5-10whp difference.

Attachment 195706

So yeah, only like a ~30whp difference.

Allright, here's a few:

http://flyinmiata.com/tech/dyno.php

http://forum.miata.net/vb/showthread.php?t=342323

And here, Jay's done it.

And that's just FM charts and you know there's many "FM cars" more out there which aren't on that website.

Sav, I saw your graph and I "believe" but for the $, when it comes time for me to try one out I will do a same day back to back.

18psi if you really believe that having an IM is a prerequisite 300+whp that's asanine. If your turbo can handle it, moar boost will get you there. Don't be obtuse. As I said before, have you considered the frikken map? He didn't reply to my question about timing. Maybe his map is fucked, maybe the timing is untuned. Regardless, he can easily see over 300 with bigger injectors and more fuel. BTW it was a sawzall...

I also don't like this shit too much because while the intake is not a closed system, it seems like the forum (collectively) is forgoing engineering. Does anyone know what the volume of a stock intake + runners is? What is the volume of X replacement? With the runner length, what power band should we expect to improve? What's the volume of the plenum and how does it compare to a stocker?

I understand strapping one on and seeing what kind of difference it makes but who knows, maybe the results would be much more dramatic if it was sized properly and most of the intakes I've seen out there are smaller than what the maths tell me they should be.

If you say BEGi cast mani, it's known what you're talking about.

So your argument is that because we cannot spend the money to fully optimize the intake manifold, we shouldn't bother at all? I've gotten a quote for the kind of engineering work you're talking about, and it goes way, way beyond plenum size and runner length. Throat angles, cross-sectional area at several points down the runner, portmatching, etc, etc. Just the design quote was more than I have into my current IM, and then they wanted like 2-3x that for sheetmetal fabrication. It might get me 60whp instead of 30, and it might get me 35. Someday when I shit gold I'll go have that done, but in the meantime I'll put my money into other places.

You can raise pressure or increase flow. Or both.
Reason people on here get bigger turbo's, head work, cams, tubular exhaust manifolds, and free flowing exhausts is why?
FLOW.
More flow = less heat = more power at less pressure.


I get your point about no one REALLY doing thorough tests on stock im vs the sheetmetal ones, but then no one REALLY did any tests on the absurdflow and other tubular exhaust manifolds either to prove that they flow better than the BEGi log, yet everyone and their mother will agree that they flow more.

Still ambiguous ;) despite context clues and assumption through understanding of general forum dialect, I still dislike that I thought he may have had a BEGi cast intake manifold when I first read it ^_^

Exactly. Intake manifolds can get real expensive, real quick. Not only is proper design expensive but also the fabrication.

The honda skunk manifold is popular and therefore "gangbanged" because it is cheap and proven to be effective on a similar engine.

levnubin is in florida

Ok this is the shit that bugs me. Just because everyone thinks a part is better doesn't mean that it is better part. What's missing is the quantification. That is the distinction between theory and practice right? And since we're spending our $ on it we should take the time to find out what the specific improvements are (if any).

I will paypal anyone who has a NB mani the $ for a back to back dyno on the hybrid and stock mani, with fueling adjust for the same AFR targets.

Ok this is the shit that bugs me. Just because everyone thinks a part is better doesn't mean that it is better part. What's missing is the quantification. That is the distinction between theory and practice right? And since we're spending our $ on it we should take the time to find out what the specific improvements are (if any).

I will paypal anyone who has a NB mani the $ for a back to back dyno on the hybrid and stock mani, with fueling adjust for the same AFR targets

We aren't fools, we think the parts are better because people have seen specific results that show it. Trey picked up 800rpm of spool going from a BEGi cast manifold to his AF setup with no other changes. Same turbo, same catback exhaust, same intake manifold, same AFR targets. Sure, nobody bolted each one to a flowbench, but most of us don't have the resources to make those measurements.

Can you provide an example of a part that everyone assumes is better without any evidence at all?

How about some more details here. Are you looking for the only change to be just an intake manifold? If so, good luck because most people also change out the throttle body as well as alter the cold side intercooler piping. All of these items make a difference. Are you also willing to cover the entire dyno cost, not just the one money pull?

stock vs modified Intake + TB + intake piping makes sense. I'd pay $100 for the comparison. That would be worth the r&d time to me. Preferably on a larger frame higher boost setup like yours.

Do it Jay:)

Too bad it would cost me much more than $100 to do this. Perhaps you should try and do this for that amount. When I finally get one of these manifolds I'll see what I can do, but it won't be for quite awhile.

Wow, lots going on here.
The very simple point to my post was that I believe the OP can have his turbo spool up much quicker that it is in that plot.

As for my mountain shaped TQ curve, well, thats how it is. That is with a gutted 99 intake manifold. The TQ drops pretty quickly, but the HP continues much better than it did witht he IM in stock form. I gained about 1000rpm more or usable hp.

theres lots more to be had from that engine, thats for sure, my "laggy" 3076 goes to almost peak tq, at just over 4k, and stays in that area for a long time.

we used engine analyzer pro to help with the design of the inlet manifold, to match the rest of the setup of the engine, and driveability is excellent. It also lacks the "diesel" powerband some engines seem to have, with just a small window where the engine is working properly. smooth gradually increase in power to the point where the cams will let go.

Attachment 195599

I like how the wastegate is opening right at 5252, haha

That is a beautiful torque curve, it's flat but it even increases slightly. I imagine your acceleration is at a near constant rate. I aspire to match such beauty! How is throttle response though with such a big turbo?

throttle response is wicked and it feels like a linear pull from 3k rpm to 7500.
modulating throttle mid corner is easy, and the power is almost instant.

I just noticed I was looking at the red/blue instead of the yellow/orange. either way, both are good torque curves and I agree with you on that "diesel" nonsense everyone seems to have. Do you have any pictures of your manifold? or if willing to disclose, some of the "design specs" of the manifold

with the 2871R 0.86 on my 1.6L there is very minimal lag. the power is high enough all the way from 3500-ign cut that you RIP through the gears.

but i need a 6 speed and rods to go more hp than i have now.

nickC, check my build thread, lots and lots of pics etc.

https://www.miataturbo.net/build-threads-57/hf-mx5ts-3076-turboed-trackday-street-toy-38472/

115 and 140 ft-lbs @ 3500 and 4000 RPM respectively

vs

180 and 250 ft-lbs


BIIIIIG difference.

Something's wrong with wes65's setup. Leaking piping / BOV perhaps causing ultra slow spool.

3in flow master chambered muffler. ive told him about it before, but he likes the sound. there are a few other thing i suggested to him, like intake manifold and new rear end gears, but he is talking about selling the car so i dont think he is too concerned with those issues. sucks cus its a damn quick car. it made me want a miata 2 years ago when i met wes and did some street tuning for him. ill be sad to see him sell his car.

I did it over 8 years ago. I also tried a BEGi and Modified Honda and they did make more power at the top.

350hp on a Miata Motor is very easy and a simple receipe... Here it is...

720cc or bigger injectors
HIgh Flow Fuel Rail
Forged Rods
Stock 94-97 Pistons
T3/T4 50 Trim Turbo, or GT3071 Turbo
Good External Wastegate
3" Downpipe to 3" Exhaust with 200 Cell Cat.
Standalone Tune by someone who knows what they are doing.
18-20psi of Boost.

Voila.. 350hp!

Thanks, Marc
M-Tuned.com

I can test it on my GT2560 @ 10 psi setup, but it will have to wait a few months until I have some time. I'm getting married in 2 weeks and going away for almost a month.

We have a dyno in house..

Marc
M-Tuned.com

Marc, what octane?

Are the stock 94-97 pistons really good for 350 whp?

What would your list look like if the goal was at least 400 whp?