Miata Turbo Forum - Boost cars, acquire cats.

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-   -   Who will i be running with? (https://www.miataturbo.net/prefabbed-turbo-kits-3/who-will-i-running-3963/)

ruger988 07-13-2006 09:13 PM

Who will i be running with?
 
Got my greddy kit sitting under my bed waiting for time to be put on...already got a brainstorm dual exhaust and high flow cat on the car......otherwise it's a stock 1990 5spd. The few turbo accessories i've got building up right now are the ETD crossover pipe, 1.8 inkector and im planning on ordering te bipes with part of my paycheck tomorrow. With all that said....what kind of cars can i be expecting to run with? SRT4s....V6 mustangs.....just wondering roughly how much crap i'll be able to talk at work now...LOL...(work at advance auto)

Mach929 07-13-2006 09:56 PM

v6 mustangs shouldn't be a problem, srt4s will still spank you

that7guy 07-13-2006 10:52 PM

Without the , i would out walk you in the low RPMS. An upgraded Downpipe will rbipeseally help you out! Depending on how much boost your running you should be able to keep your own. Are you running Autocross or just street racing? If turns are involved you should do rather well but in a straight line that rear diff is going to blow real fast when you go hard off the line. Why dont you just install the kit and then let your butt dyno do the talking!

Mach929: As in MC, MD?

Pop VII 07-13-2006 11:03 PM

There are a few lists out such as this one. http://www.albeedigital.com/supercou...0-60times.html

The basic kit install should shave about 1.5 seconds from the 1/4 mile and ET around 15.5. Will let you figure out what you can beat! The 1.8 injectors will add a slight handicap to the time and adding a Bipes would add a very slight advantage.

ThePass 07-14-2006 03:49 AM

Remember, you are asking about the basic kit. The basic Greddy turbo kit is the absolute bare minimums that you need to run a turbo and it operates at 4.5-5 psi which is really ridiculously low - but thats all the stock setup can support. You're only going to net about 135 hp to the wheels at 5 psi - so a 15.5 is a very surprising time with so little power. With how light the car is the times drop a substantial amount once you start adding boost and horsepower.

First thing on your list should be atleast a bipes unit - the big reason you don't get a better time than ~15.5 with the stock kit is because with just the Greddy kit you have no control over timing - and to be safe on the engine you have to set the base timing at something ridiculously conservative like 6 or 7 degrees. This means that all the way up until you hit full boost the engine is giving you severely less hp and especially torque than you should be getting. With a bipes you can keep base timing near 12-13 degrees and you will regain that torque.
-Ryan

Pop VII 07-14-2006 07:02 PM

I don't agree, but could be an interesting discussion. A few observations.

He has a free flowing exhaust so adding a basic average 4-5 HP to the rear wheels over a stock system. From that point the basic calculations for each PSI of boost is compounded. The high flow CAT gain is so insignificant we just ignore it, or just add 1/2 HP to the equation.

On a drag strip will be side-stepping at around 5K RPM, and RPMs should not drop much below that figure so the Bipes will not really have much function since already at full retard for nearly all of the 1/4 mile run.

samnavy 07-14-2006 07:53 PM

Pop VII is right, 15.5 isn't unreasonable... at least a few times.
Check out this website for the info you're looking for:
http://www.albeedigital.com/supercou...0-60times.html
As for V6 Mustangs, I wouldn't try one of the new ones:
2005 Ford Mustang LX 4.0l 0-60: 6.9 1/4mile: 15.3
but the older ones go ahead:
1995 Ford Mustang 3.8 0-60: 9.9 1/4mile: 17.3

Ruger, I'm sure you don't want to hear this, but I'm also sure you want to have the Greddy in for at least a few weeks before you have to put it back up on the jacks. 5k RPM boosted clutch drops are not a good idea with a stock clutch. In fact, boosting period isn't a good idea with a stock clutch. When you do finally get it installed, take it easy off the line for awhile. A Spec or ACT is a $350 proposition if you do it right, and do it yourself... or $600 (or more) installed. You might want to seriously consider stepping up to a Stage 1 type clutch at the same time you do the turbo install.

YOU WILL NEED A NEW CLUTCH SOON AFTER GOING BOOSTED.

This is not from experience as I am not yet in the boost club... this input is from a year of inpartial searching, lurking, and soaking in as much as I can... so when my funds come in, I do it right the first time and only have to enjoy my efforts, not repeat them once a month replacing things as I break them.

nyuaznguy 07-14-2006 09:23 PM


Originally Posted by Pop VII
There are a few lists out such as this one. http://www.albeedigital.com/supercou...0-60times.html

The basic kit install should shave about 1.5 seconds from the 1/4 mile and ET around 15.5. Will let you figure out what you can beat! The 1.8 injectors will add a slight handicap to the time and adding a Bipes would add a very slight advantage.

Hi Pop,

Any reason the 1.8 injectors would be a slight handicap?

I just put them in my car... now i'm thinking i might regret it.

Pop VII 07-14-2006 10:53 PM


Originally Posted by nyuaznguy
Hi Pop,

Any reason the 1.8 injectors would be a slight handicap?

I just put them in my car... now i'm thinking i might regret it.


The response was pertinent to the 1/4 mile run. Will be in open ECU loop the entire trip. The extra fuel dumped in open loop combined with the supplied Vortech is too much fuel in places so will lose some crispness and power.

No need to regret using the 235s for street driving since most will be in closed loop where the O2 sensor signal is used by the ECU to lean out the mixture properly. Tried them for a few weeks and did not like the cold start running stumbles and idle. They are adding about 20% more fuel than needed for all open and safety default loops. At some point when you improve the fueling ie. fully adjustable AFPR, you can adjust your fueling for boost applications.

MiataNuTca 07-14-2006 11:06 PM

Going with bigger injectors and no ecu can also effect your emissions testing. Wait to upgrade the injectors until you get a Link, emanage, e-u, etc.

Pop VII 07-14-2006 11:29 PM


Originally Posted by samnavy
.... YOU WILL NEED A NEW CLUTCH SOON AFTER GOING BOOSTED. ....

Not fully agree with that either. Look on my pages under Greddy II/engine Swap and see an OEM clutch with 165K miles on it. Over 120K of those miles was with an 8 PSI turbo and periodic small shot of nitrous. I would say the need for a performance clutch would be boosting around 10 PSI.

Side stepping at 5 K RPM should not add much additional wear to the clutch. It is still a shock to the entire drive train and the burning tires act as a clutch. With that said I do not street race and have nothing to prove to anyone at a red light on public streets.

Sitting on a shelf behind me is two bracket trophies from local competion. Multiply those by about 10 for the drag events I did not win. Included is 21 Solo II trophies. Multiple that figure by about 5 for the additional events I did not place in.

Clutch wear is primarily caused by excessive clutch riding. Know no poster here is guilty of doing that but since most seem to have previously owned Miatas, we don't know how the PO drove it.

firedog25 07-15-2006 01:52 AM

I'll even one up you Pop...

I have a VALUE LINE clutch and it's held up to the turbo. I have a 2.5 exhaust going on in a couple of weeks though which should bump the power significantly. We'll see how well it holds up to that.

that7guy 07-15-2006 03:02 AM

Of all my mods to the engine im still running stock clutch at 6psi, 2.5 dp/ exhaust ect ect. No problems whatsoever. I am planning an upgrade along with the flywheel around 8psi though.

Pop VII 07-15-2006 11:56 AM


Originally Posted by firedog25
...I have a VALUE LINE clutch and it's held up to the turbo. I have a 2.5 exhaust going on in a couple of weeks though which should bump the power significantly. We'll see how well it holds up to that.

Those pix and page is 3 years old and is also a $95 Value Line clutch kit. Unable to detect any slippage or drivability difference between it and the OEM removed at 8 PSI. At the time I put it in was unable to locate a 1.8 flywheel at a price I was willing to pay so stuck with the 1.6 kit. Price was the same for either kit.

I have not added the nitrous to it for testing to see if there is any difference. The additional 34 HP shot caused some fairly bad slipping, so COMPUCAR made me a new 19 HP button. That was about 9 years ago. Sometimes that would slip a little, so is how I arrived at an approximate 10 PSI limit.

My exhaust system it a two piece Pacesetter ($99 11 years ago) cat back. It has an ID of 2 1/4" vs the 1 7/8". It provides a cross section increase from about 2.75" to 3.94". Quite adequate for my needs. No question of the power increase ... not really detectable much by seat of the pants ... more audible from a smoother easier breathing sound and less engine labor.

TurboMiatKid 07-15-2006 12:02 PM

Im running like 6 psi and at high RPM's it slips on me a bit. But i dono, wanting to up to a stage 1 or 2 clutch. And Bosting to 10-12 psi. Ruger if you have the money and plan on bosting it up later down the line, i would pick one up.

qtwre 07-15-2006 03:36 PM

I dunno... 10psi here with the stock clutch. It seems fine, though I don't usually drive all over in boost. If there is a slip I haven't noticed it.

firedog25 07-15-2006 06:50 PM


Originally Posted by qtwre
It seems fine, though I don't usually drive all over in boost.

I think this has a lot to do with it. I don't roll around constantly @ 6 psi either, in fact past second gear I'm rarely in boost. Of course, I do nail it every once in a while, it's just BARELY off the pace of my stock WRX. With the 2.5" turboback I should be a little quicker than... but then I plan on the Prodrive Power Pack Stage 2 next year for the WRX which should be good for 200 wheel hp. :D

Back on track, I'll try to get a dyno run before and after my 2.5" turboback. Try, no promises. Bearing in mind I have much heavier than stock wheels (Koenig Rewinds).

nyuaznguy 07-15-2006 10:52 PM


Originally Posted by MiataNuTca
Going with bigger injectors and no ecu can also effect your emissions testing. Wait to upgrade the injectors until you get a Link, emanage, e-u, etc.

Well I already failed, but I goto a very honorable :bigtu: shop in my area, and was able to pass the second time they tried ran the emissions test.

medisyn 07-15-2006 11:55 PM

after about a year of the base kit at 6psi+ intercooler my clutch is pretty much dead. But this is a 16 year old clutch we are talking about :gay: . I am looking into getting an rps max but I am always broke!

magnamx-5 07-16-2006 12:44 AM

you won't be decimating alot of car but you will surpise them i would just wait quietly in the corner until someone rolls up and when they just barely or don't get past you then the look of surprise on there face is priceless.:bigtu:


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