69 replies to this topic

[shedguy]

In this months Sportscar magazine the CRB is asking for your input to help with the parity of the 94-97 Spec Miata. It sounds like they are asking for weight and plate changes,maybe more. Please send them your thoughts. www.crbscca.com

[Diller]

Done!

[Mark Drennan]

It's about time, done!

[tom1977]

Input sent...

[Steve Scheifler]

I don't know enough about it to offer an opinion. Can someone provide arguments for and against?

[Danica Davison]

I also do not know enough to provide input on this.  However, watching Jeff Labounty finish top 2 at Daytona 4 race weekends in a row in his '94 and nick malatesta in his '97 finishing in the top 10 makes me wonder how much of a difference there is, or if it was just the draft helping them stay up front? 

 

There may be some difference noticed from Todd Buras, who at the turkey trot in an OPM 1.8 was qualified in around 8th or 9th, over a second off danny and selin...where if he were in his VVT, would have probably been a little closer to the front.  I am sure there are other factors that could play in that as well, as far as level of prep goes.  I think that car has been around for quite a while.  Maybe Danny, Fowler, or other OPM guys could comment if they did any data or other analysis comparing Todd's run in the 1.8 versus the 99/VVT that weekend that they would be willing to share.

[Danica Davison]

^ Not trying to dive into too big of a parity discussion here.  I am just curious on if any data was collected that weekend and if the OPM guys would be willing to share. 

[Jim Drago]

I also do not know enough to provide input on this.  However, watching Jeff Labounty finish top 2 at Daytona 4 race weekends in a row in his '94 and nick malatesta in his '97 finishing in the top 10 makes me wonder how much of a difference there is, or if it was just the draft helping them stay up front? 

 

There may be some difference noticed from Todd Buras, who at the turkey trot in an OPM 1.8 was qualified in around 8th or 9th, over a second off danny and selin...where if he were in his VVT, would have probably been a little closer to the front.  I am sure there are other factors that could play in that as well, as far as level of prep goes.  I think that car has been around for quite a while.  Maybe Danny, Fowler, or other OPM guys could comment if they did any data or other analysis comparing Todd's run in the 1.8 versus the 99/VVT that weekend that they would be willing to share.

Pretty big difference in cars with Todds 1.8 and his VVT.  His VVT is a majors winning car.. The orange car has been shelved for awhile and bought back as is  it was his original pro car back in 2004.   

The answer ( IMO) for the 94/97 car is a relatively simple one. The car has always been a tweener... Adjust/remove the plate to achieve 99 like performance, then match the weight to the 99. The car then should race like the 99.  Perhaps deduct 15 lbs for suspension geometry, but most tell us it isn't needed 

[38bfast]

My personal opinion is the 94-97 is the best year to build from. The ecu/electronics are just smart enough to get the job done very well. The car doesn't have nearly as much of the parts variation or the pesky A/F flapper door to deal with. It also is better than the more complicated 99-05 with pesky wiring / sensor problems. It also does not have the complication of VVT or VIL that have proven to be issues. So I conclude that is the most reliable / cheapest variation to bring to top prep. Unfortunately it is not on anyone's "A" list of cars to build today. As well as their market value is no where near 99-05. Many 1.8 have been parked or sold in favor of the newer models. Same boat the 1.6 is in.

Is the car not competitive perception or reality?

[DrDomm]

The car doesn't have nearly as much of the parts variation or the pesky A/F flapper door to deal with. It also is better than the more complicated 99-05 with pesky wiring / sensor problems.

 

Can you provide a link, or just explain, "the pesky A/F flapper door" deal?

 

And what about the '94-95 vs. '96-97 OBD1/2 difference?

 

Just curious.

[38bfast]

Can you provide a link, or just explain, "the pesky A/F flapper door" deal?
 
And what about the '94-95 vs. '96-97 OBD1/2 difference?
 
Just curious.

Referencing the A/F meter on the 1.6 as being difficult and inconsistent to tune. That the 94-97 does not have to deal with.

The 96-97 obdII has a bit flatter A/F curve.

[Jim Drago]

Can you provide a link, or just explain, "the pesky A/F flapper door" deal?

 

And what about the '94-95 vs. '96-97 OBD1/2 difference?

 

Just curious.

 

 

Domm

In short the 1.6 afm has a door inside it. It can actually act a little like a restrictor plate at times. Many tune the tension on the spring that controls this door. This door also closes under G loads which is why people rotate etc and try and find the best of both worlds.. all the while this changes a:f  ratuio. It is a bit a of a PITA

Jim 

[DrDomm]

Thanks, guys.

[CarbonRacer]

Well since my name was mentioned in this post I feel I should respond. I was delaying my response waiting for the CRB to make their decision on if they are going to help the NA 1.8 which they have decide not to do anything to help the NA 1.8. Myself as well as many other NA drivers have sent in letters with requests and suggestions to help the NA 1.8 be more competitive against the NB car and all the letters were rejected.

 

I have been driving two different 1997 NA 1.8 for the past 6 years with the same results against the NB cars. The plate was changed from 45mm to 47mm in 2015, back to it's original size from a few years ago and honestly the only thing I noticed is the NB cars do not pull away as bad on long straights. My lap times barely changed after the plate change.

 

I have done multiple test weekends and run SM class and ITS class (WITHOUT THE PLATE) and my car averaged .4 - .6 tenths faster lap times in ITS with everything else being the same. The reason I ran ITS is to compare my NA car against the 99 NB cars that kept the car in SM trim with the plate in the car. Even though I did not have a plate I still had a hard time passing the 99 NB cars but it could done.

 

The best track to give an example is running Daytona since it was mentioned above. The 1997 NA 1.8 runs well at that track on the infield but loses on the top end of 4th and 5th gear. If a 99 NB is in front of me and there is a gap I cannot close the gap on the long straights by myself BUT if a 99 NB is behind me and there is a gap they can close the gap and be right on my bumper and drive around me before the next turn with no bump draft help. This has happened to me for years lap after lap and many different 99 cars and drivers. I have been at the track when Jeff LaBounty won a couple races at Daytona in the last couple years with his 1997 NA 1.8 but to my knowledge he was hooked up with his teammates Cori and Alex but I don't know the details because I wasn't at the front to see how it unfolded. Also, if my memory is correct most of the top drivers were not at the track on those weekends. Since those couple wins Jeff had with his teammates that NA 1.8 car has not finished in the top 5 ever again.

 

Jim Drago even mentioned in this post that the NA 1.8 should have the plate pulled and the weight matched to the 99 cars and even has the dyno numbers listed on his engine advertising that clearly shows the power difference.

 

"The answer ( IMO) for the 94/97 car is a relatively simple one. The car has always been a tweener... Adjust/remove the plate to achieve 99 like performance, then match the weight to the 99. The car then should race like the 99.  Perhaps deduct 15 lbs for suspension geometry, but most tell us it isn't needed   :)"

 

01/05 engines 127/129 hp dynojet sae $6500.00
99/00 engines 128/130 hp dynojet sae $6500.00
94/97 engines 124/126 hp dynojet sae $5950.00
90/93 engines 123/124 hp dynojet sae $5950.00

These engines are built with all new parts from Mazda, we push every tolerance to get the most HP we can.

 

http://mazdaracers.c...racing-engines/

[Erik Hardy]

When I pulled the plate on my NA1.8 a few days ago on an Eddy current mustang dyno that has been less than 0.5hp variation during entire dyno sessions, the result was a 3hp delta.

Ive spent too much time at the dyno lately because 1.6 cars have all the fun but I intend on bringing the 1.8na back to the dyno soon so Im open to ideas...

[38bfast]

Carbon racer the SMAC is monitoring the data concerning the 1.8. It's not a dead issue. The difficulty is there is not a lot of them out there to get a good sample size.

[38bfast]

When I pulled the plate on my NA1.8 a few days ago on an Eddy current mustang dyno that has been less than 0.5hp variation during entire dyno sessions, the result was a 3hp delta.
Ive spent too much time at the dyno lately because 1.6 cars have all the fun but I intend on bringing the 1.8na back to the dyno soon so Im open to ideas...

Eric the SMAC has been provided with data that closely supports your testing. The question is what does that do to lap time. Same day / conditions / driver. Plate vs no plate. As well as a Sample from the a top prep car.

[Erik Hardy]

I trust the lapsim efforts because they all dwindle down to F=MA. So for Jason's lapsim at Mid-Ohio 8hp / second, +3hp equates to -0.375 quicker lap. 

[Steve Scheifler]

That sounds a bit high to me, but maybe. I assume that number works only starting from a current typical SM, and each additional second requires significantly more power increase than the last.

Surely there are people with a lot of experience at Mid-O who have tested with and without a plate. Perhaps they will share?

[Erik Hardy]

Surely there are people with a lot of experience at Mid-O who have tested with and without a plate. Perhaps they will share?

 

I guess I don't qualify as significant Mid-Ohio experience, however, my findings on the dyno correlate to my STL races with about 1mph increase on the main straight.

 

Top prep or not, the components that absorb power will absorb the same amount of power with or without a restrictor plate