Bought a Volvo V50, now I feel like my Miata is slow
 

The volvo has a 2.5L 5-cylinder turbo making an unknown-to-me amount of boost.

It's rated at around 230hp and 235 lb-ft of torque. The power to weight ratio is probably similar between my two cars but the volvo has full torque at like 1500 rpm.

After driving the volvo for a few days in a row, switching to the miata feels disappointing (at least in regards to acceleration). In the Volvo a quick jab at the throttle at low RPMs creates a satisfying lurch forwards. The miata, in comparison, feels sluggish until it opens up around 3500 / 4000 rpm.

SO, to all the owners of fast miatas, what are your tips for generating more juice down low? Is a 3" exhaust a good bet, or do you reallly just need more displacement for good low end torque?

What turbo are you running? What exhaust? At 10psi you must be maxing out those 305's. Tune? Timing?

Should be hitting the limit of 305's at around 8psi, definitely 10 without a fuel pressure riser. What are your air/fuel ratios?

Smaller turbos are the cure if you want more power down low, but obviously you'll be sacrificing your top end powah a bit. I'm running into that problem in my Greddy setup. Great power starting as low as 2000rpm, but once it hits full boost at 4000, it just sits there at the same power/acceleration until redline. Still fast though.

damnit, i wrote a whole reply and lost it.. here it goes again :)

I have a begi-s with gt2554 turbo. Kept the FPR with the 305s, can hit 10.0 AFR under full boost.

Fuel & Timing is tuned on the street, no dyno time.. local guy quoted me "125 for three pulls". I don't knwo if that's enough time to really do anything so i haven't gone yet :)

Current timing map attached, maybe that's part of it?

Oh -- my exhaust is a 2.25" stainless steel "made in china" deal w/glasspack exhaust. the cat is by magnaflow.

-Tomaj

More boost, bigger exhaust, tune. :)

(just realized i forgot to attach timing map -- will get it in a minute!!)

no offense, but if you think your volvo is fast enough to make the miata seem slow your miata must be SLOW AS BALLS


Generating more torque down low can to a certain point be done by retuning timing down low. opening up the breathing also helps.......or you could just get a tiny ass turbo (like the one on the volvo) and gain a shit ton of lowend/midrange at the expense of your topend

He already has a 2554, can't go much smaller than that, really.

@18psi -- LOL no offense taken.

That's the other thing.. i've never driven a 'fast' turbo miata so i'm not sure what exactly it should feel like when set up right.

Maybe i should just bite the bullet and do a dyno run just so i know where i stand, maybe that'll give more information on what to do next/

I'd guess around 170-180.

There sure is. Have you seen how small those volvo turbo's are? ESP when compared to their engine size. Put a turbo on the miata that is roughly the same ratio of turbo/engine as the audi and you'll have a shitton of torque down low/midrange. That would be fail though, since the topend would be utter shit just like it is on the volvo.


Its nice to have lowend torque on a daily driver, I know EXACTLY how OP feels.

Semantics, sir. There are smaller turbos, but as you said, they would be complete fail on a Miata.

Low end torque in a 1.6L Miata costs money, how much do you want to spend??

A 2L FE3 with custom turbo manifold and BB 2560 would pull like a freight train.

The same turbo on a 1.8 BP would also have good low end.

If you want 8-10 psi boost by 2,200 RPM (and don't want to run more than 10psi), put on an Aerodyne or Aerocharger VATN turbo (don't expect it to last as long as a Garret)

If you want the best of both worlds with a 1.6L, run a compound setup with T28 sleeve turbo blowing into a supercharger.

Using an RRFPR with a fully tunable ECU introduces a variable that isn't needed. Sell the RRFPR and the 305's and get some RX7 550's and dial in your tune. At 10psi with the 2554r and a 2.25" exhaust, I'd say 180-190whp is about right... but you'll never know without a dyno. I don't think you'll see a huge WHP jump by switching to a 3" exhaust, but you'll see a big torque increase and probably see full boost a full 500rpm quicker. Besides a tune with bigger injectors, a bigger exhaust is what you need.

How are you tuning timing? What map are you using?

$125 for 3 pulls is a crock of shit. That's what all the Socal AWD dyno guy get because there are so few of them and they'e alway full. But a simple 2wd dyno on a mid weekday should be $50 for a set of baseline pulls or I'll just do without.

samnavy, i hear you regarding the extra variable of the FPR... I"ll keep an eye out for a set of injectors and once i get them i'll do the swap and pull out the FPR... Know anyone who wants one? :)

I'm not really tuning my timing.. I'm sure i'll get flamed here but i just look at what everyone else is running and try to pick what seem like safe numbers.. Way back before i got my IC and megasquirt i used to get knock, so i know what it sounds like (i know there's various kinds, even inaudible).. i haven't heard anything remotely like it and i don't drive that crazy so i figure i'll be OK for now.

@sn95 - i've read enough horror stories to not consider the aerodyne.. sounds like really neat technology but i don't want the headaches. Eventually if my engine ever dies i'll consider getting a 2L if my budget permits, or at least definitely a 1.8L.

Do you have a link to where this has been done on a 1.6?

sure if you search on m.net you will see the twincharge lunacy totally unnecessary, and overcomplicate imo.

To the OP i suggest more timeing and more boost. A properly tuned WI system will help you with both.

10:1 AFR isn't helping you out.

jayc72 -- you're right that 10:1 is too rich, i'm just trying to make the point that I *can* hit that number.

My targets are as
11.8 @ 170kpa,
12.0 @ 150kpa,
12.8 @ 130kpa,
14.2 @ 110 kpa
14.7 @ 100 kpa-30kpa

How do you like your enthuza 3" exhaust? Did you get the regular or budget model?

-Tomaj

P.S. timing map is finally here :)

Not if you really want good fuel economy, good low end torque and good high end power out of a small displacement engine; all small displacement vehicles don't weight 2,200lbs and have manual transmissions with stiff rear end gearing! Compounding requires a LOT of engineering to work properly but it will give good low end torque and high end power. If you watch the OEMs you'll see that a few of them (VW comes to mind) already have compound setups in production. Superchargers for compounds are generally easier to install on V-engines that inlines (supercharger rests nicely in the valley). Sequential turbochargers would be easier to engineer and install on a inline Miata engine and would provide most of the benefits of a compound setup.

either way you're going to want a better exhaust. i'd actually get a bigger turbo and forget about the bottom end you're never going to get anyway, and this way you'll be able to get the 220+whp you need to be fairly quick

You should be fine with your 2554 unless you plan to push more than the low 200 hp range. The exhaust sucks but hard to say how bad it's hurting you. I'd say first step is get a little bigger injectors and find someone to help with tune.

A 2554 should be spooling quick enough to feel good under 4k. Log a few runs in 4th gear from 2500 rpms until you hit full boost. Let us know what your spool is like. X psi at 2500, 2750, 3000, 3250, 3500, etc.

Dump the 1.6 and put in a 1.8. The difference in low-end torque between these motors (both turboed, of course) is night and day. You'll need a new exhaust manifold and downpipe, and should upgrade your exhaust, injectors, etc. In return, you'll reach your stated goal of making your Volvo seem slow.

we arent talking about all vehicles we are talking about miatas fwiw i have good low end and high end hp and good fuel economy. You only pay for the horses you use man. Twinchargeing is a waste.

I'll probably pick up a 3" exhaust, see what difference that makes.

a 1.8 would be nice but i'm not nearly technical enough to install it myself so i think costs would start getting out of hand (engine, clutch, flywheel, injectors, mani, dp)

-tomaj

lol its not that hard to RR a motor your main issue would be $ though cause it means a whole new setup just about.

WTF? who in nj is charging 125 for 3 pulls?! Dayum. There's the semiannual miatatturbo dyno day in delaware, 60 for a shitload of pulls. Get with it man! Christ. See lots of setups and talk to lots of guys who mostly know what they are doing.

There's a guy around the corner from my house "ATX Motorsports". I'm pretty sure he said $125 for 3 pulls.. That was over a year ago, so maybe more now, maybe less..

Delaware's like 4 hrs' driver from here! My wife won't let me off the leash for that long ;-)

i suggest you hook up wif turbo tim he can get you time cheaper than that i am sure. hell i can get a full hr of dyno time for that in ky.

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Bitch that was a mistake!

My sister has an S40 T5, it will chirp tires on crosswalk paint if you aren't careful. It's silly how much low end power that thing has.

3" exhaust will help, getting a real tune will help.

I think you should go for a ride in a miata that has the same power.

I think everyone answered your question. Bigger injectors, tune it, 3" exhaust turn up the boost.

That tiny ass turbo should have you spinning tire all over.