James Theriot

26s are on with the new coils. I need to crank the coils up some more and do some more pursuading. For some reason the driver tire is touching the body behind the door and the passenger side still has a gap. Is there any way to correct that? Or do i just need to replace all my bushings?

James Theriot

Well tires are on and went out today to test and my flyin miata clutch is slipping. Theres no way my car is making the torque to cover what they claim it should hold. Not quite sure what I'm doing next.

IanIsInTheGarage

There are two clutches they offer. I'd say go up a level if your not already at stage 2. Also it's possible something has contaminated your clutch/flywheel surface and causing the issue.

James Theriot

I made sure to check for oil contamination and found none. It started slipping soon after some abusive launches, I'm sure I only glazed it for now and that some normal driving will return it to its former glory.

The car has me very confused as I am running 13 psi with 460cc injectors and my datalog shows 100% duty cycle at 7200 rpm. That maths out to a decent estimated horsepower number.

I understand its an estimate, but before i noticed the clutch slipping my best mph in the 1/4 has been 96 mph. Which maths out to barely faster than stock.
I'm running 93 octane and a decent timing map. And almost a rock solid 11.5 afr.

hks_kansei

Could be alignment, since by it's nature, adjusting the toe will move the wheel fore/aft slightly.

Since you're drag racing you'll probably want to replace the bushes anyway. These cars axle tramps pretty badly, so you'll want to do as much as you can to prevent that

James Theriot

I've checked rear toe and it is good. I plan to replace bushings as soon as I start seeing that the money I have already spent is having a positive effect. Right now i have a turbocharged car with a clutch that should hold plenty of power, 6 speed transmission, and slicks on the car and its hardly faster than stock.

Newaza

From what I can find from others it looks like 96 mph in 1/4mile is roughly about 10mph faster than a bone stock stock 99 and should be good for very low 14 seconds. I see you want to run in the 11s 1/4 mile, so youll need more power than what you have now by a lot.

How is your fuel system set up? What pump are you using and are you using a boost referenced regulator or the in tank non referenced regulator as came stock on 99 models?

James Theriot

I am running the stock 99 pump and regulator with 460cc RX7 fuel injectors. I understand that I need more power to get into the 11s, but I feel like the car should be running better than it is on 13 psi. I dont want to be turning up the boost to get to a specific number.

Bone stock it ran 16.28@83 mph
4spi it ran 15.45@92 mph
Now on 13 psi 14.67@96 mph

I just dont feel like I am getting the performance out of it that i should be. The 13 psi run is the only one that I've had slicks on the car.

Newaza

Hmmm 9 additional psi and only 4 mph. something does seem off.., but still a whole lot faster than stock. What was your 60' and 1/8th mile time?

You may want to start a new thread asking as a question. It will likely get the attention of someone who has run same boost level as you at the track and can say where you should be.. They will need to know as much about your setup as possible to compare apples to apples. Such as turbo size, downpipe size, timing map etc...

Newaza

I just noticed you are using turbonetics 61mm inducer turbo. Is that their 60-1 frame size? How high are you revving at your shift point and how low do rpm's fall after a shift? I would have to look at the map for that turbo, but for a 61mm inducer compressor wheel and a 1.8l motor you would typically need to shift at roughly 8000 rpm to keep engine above the surge line at all times while in boost after a shift. You may be riding the surge line if shifting any lower rpm. To use what that turbo has to offer you are going to need to spend some $ on pistons and rods as well as upgrade fuel pump, injectors and go to a boost referenced regulator. Might be better to consider a smaller turbo until you have everything in place to support that size turbo.

James Theriot

I think you are correct Newaza. The car feels like it makes good power in a small area and when drag racing I dont think I am in that area long enough. I was shifting at 7500rpm and The gear would fall to 5000ish rpm. The turbo is something I bought used, I'm not 100% sure about the frame size. I know that the inducer is approx 61mm and that it is a T3 flange inlet with a very small turbine housing compared to other turbos I have at the house. I did a 3rd gear pull for Virtual dyno yesterday and was suprised by the number it tells me. I made the pull on a flat road and my clutch is not slipping any more.

James Theriot

Hard to believe its making that much power but i am also at 100% injector duty cycle on my 460cc injectors.

James Theriot

60 foot was 2.44 (No Launch Control)
1/8 mile was 9.52 @ 77.59

This is with me shifting between 7200 and 7500 rpm
But after my Virtual Dyno (even if the actual numbers are inacurate) I can see that the car stops making power after 6500. I want to run it again shifting sooner.

Newaza

You said you did the pull in 3rd gear but graph on vitual dyno says 4th gear. Might want to double check that. In so far as power at the wheels for a comparison I trapped last year in the 1/8th mile 106mph, that would be lower 130ish mph in the 1/4. At the time I was using a gtx3076 .82ar churbo at around 32-33 lbs boost. I doubt i was making much over an honest 400whp then.

Newaza

You may want to pull turbo and housings to actually measure the large and small side of the wheels to see exactly what you have. That curve you posted just doesnt reflect the shape of a 61mm inducer (smaller diameter of the compressor wheel) compressor wheel unless someone paired it with a stock size t3 turbine wheel and housing to force it to boost on a small engine, which makes it a mis-matched turbo. If that is what you have you would be better off with something else thats more well suited for your goals.

sixshooter

iTrader: (12)

I'm going to jump right out there and say I don't think James knows the difference between an inducer and exducer. I'm also going to say that I don't think that Turbonetics makes a turbo with a 61 mm inducer that would fit on a T2 or T3 frame exhaust housing. I'm also guessing that James has not put a digital micrometer on the compressor wheel.

I'm also going to guess he didn't put 500 break in miles on the clutch before going wide open throttle.

I could be wrong but experience tells me it's unlikely.

James Theriot

Fixed the virtual dyno gear. Much worse and more believeable at 175whp lmao.

Sixshooter Inducer would be the spinny part i see and exducer is the larger portion of the blade behind the compressor housing.

Clutch was purchased used but in good condition. I figured the last guy who drove into a pole put enough miles on it for me to make some pulls.

I bought the turbo second hand from a twin turbo mustang build. I have the other turbo on my desk at home. I'll take all the pictures and measurements you want.

Newaza

Well I had to ask to be sure there was no confusion since a stock size t3 compressor wheel is 60 mm on the exducer if I remember right which is close to 61mm. That graph just didnt look right for the curve with a 61mm inducer. Just wanted to be sure we were on the same page. Wasnt trying to insult. Also looks like you're right, Looks like Turbonetics doesnt make a 61mm inducer for a t3, but apparently they do make in a t3 a 60mm inducer compressor which they pair with a 48mm exducer turbine wheel.

James Theriot

I will take some measurements today when I get home to clarify. Either way I feel like the car is not making the power it should. Maybe my spark map is not as aggressive as I think it is. I feel like the car should make this much power on 8 or 9 psi. On 13 psi I feel that I should be closer to 200whp.

sixshooter

iTrader: (12)

I'm glad you looked that up because these two statements above don't correlate unless you have an eighty or ninety something millimeter exducer. That would be a big turbo on our cars.

A sixty something millimeter exducer will typically be matched to a forty or fifty something millimeter inducer. On our cars that is not considered a big turbo.

An interesting point that was not mentioned originally when you said you installed a new clutch.


On RX7 460cc injectors a well tuned car can go over 200whp at 85% duty cycle on a log manifold and stock NA8 head. Your head breathes better. What deadtimes are you using? What AFR are you targeting?

Virtual dyno is incredibly unreliable so I wouldn't use that as a real measure against numbers other cars are putting down on actual dynos. Just like you can't even begin to compare results from two different cars on two different dynos. The same Miata can be different by 50 horsepower on two dynos (especially in western Colorado). Virtual dyno is only useful for tuning against its own data.

Did you account for the larger diameter of those rear tires in virtual dyno?