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-   -   question about laguna seca (https://www.rx7club.com/race-car-tech-103/question-about-laguna-seca-726995/)

azn akira 02-03-08 04:26 AM

question about laguna seca
 
I just did my first track day at laguna seca today and i got popped for sound. i was 96 db instead of 92 db. i didnt have anything to make a muffler turn-down, and nobody that i asked knew where to get them. so i had to resort to short shifting and lifting when going past the sound booth. on the exit of turn 5 i immediately put it in 4th and gave it just enough gas to not boost (which resulted in 88 db) and i didnt get back on the gas until getting under the bridge before turn 6. how much time do you think i lost by doing that? im running stock turbos, fwiw. sorry if this is a dumb question.

i ended up running low 1:50's with a best time of 1:52.3xx on almost full tread street tires (kumho mx), stock turbos, and the short shift/lift for the sound booth. how does this compare you other fd owners that have ran laguna seca?

https://i5.photobucket.com/albums/y200/sbfd3s/2.jpg

John Magnuson 02-03-08 10:16 AM

It's really impossible to say how much time you lost by lifting / short shifting for the sound booth. Sounds is a real problem there especially for rotary motors. My last track day there, with a single turbo FD with THREE large magnaflow mufflers got flagged for sound until I installed the turn out. Always have a turn out available at laguna seca - it helps a LOT.

As far as your track time it seems perfectly decent for a car with street tires even if you weren't lifting. They redid the track for Moto GP a couple of years ago so it's a few seconds faster now - therefore a lot of older FD laps times don't compare.

Most stockish FDs with a decent driver without much track experience will probably run in the 1:50s with street tires and 1:40s with R compound tires so you're in the ballpark.

Without lifting a stock FD on street tires with a decent driver with a lot of track time under his belt will probably be in the mid 1:40s. I don't have any actual evidence to back this up as my FD with street tires broke last time I had it there before I got a chance to time any laps. I later rented an automatic Saturn Sky (non turbo 170hp) with all-season tires to have fun with the rest of the weekend and ran a best of about 1:53. With a manual trans I'm sure I could have brought that down a few seconds.

A fully track prepared 400hp FD with racing slicks and a driver that knows the track really well will run about 1:30 flat.

Keep practicing and I'm sure you'll continue to knock seconds off your times. Remember to fabricate a turn out for next time! Have fun! I love that track.

azn akira 02-03-08 11:09 AM

thanks for the info

RETed 02-03-08 12:48 PM

I don't know the new track, but I don't think it's good for 10 seconds?

Some old benchmarks...

Brian Richards driving Shiv Patak's project FD clocked at 1:40:xx - I believe the car was making right under 400 at the wheels and running wide Yokohama Sport's street tires at the time

Ray Lochhead first time driving his "track" FD - 2:10:xx.

Getting an FD under 2:00 would raise eyebrows.
That was considered quick.
Seasoned drivers on good rubber could clock 1:50's.
Getting down to 1:45's would be fricken' fast.

Keep in mind, this was wayy back in 1997 - 1998 or so.


-Ted

John Magnuson 02-03-08 04:03 PM


Originally Posted by RETed (Post 7821554)
I don't know the new track, but I don't think it's good for 10 seconds?

The track has not been changed a lot for Moto GP but they've smoothed out some berms and made the track smoother in general. Most agree it's good for about 1-2 seconds depending on the car.

I'm definately an amateur racer so here are a few bench marks from car's I've driven at Laguna:

2006 Miata (bone stock w/ race pad and R compound tires) - 1:47.002
2008 Saturn Sky Rental Car - Automatic - All Season tires (thanks AVIS!) - 1:53.4
1993 Mazda RX-7 (R compound tires, race brakes, stock twins) - 1:45.3 (old configuration a long time ago)

SHPNOUT 02-04-08 12:06 AM

1:38.6.............. last October. Second time at the track. I can get it down more as my lack of track experience held me back. Easy couple of secs with more track time.

Full race prep car, DOT-R tires. 92 db restriction. I run a muffler, a turn down, AND put a fully vented super trap on the end to make sound. Power really suffers.

I agree....set up a turn down on your exhaust and that should help you and you can avoid the lifting game.

justint5387 02-04-08 02:33 AM

I ran 1.53.x with my everything stock (even pads) MS3 on my first time at Laguna Seca , i believe you should be able to go quicker in a modded FD.

azn akira 02-04-08 12:57 PM

i also believe i should be able to go quicker. though i would have been a bit quicker if i didnt have to pretty much keep a constant speed between turn 5 and 6

ivegonemad 02-04-08 01:12 PM

who are you running with?? scca?? nasa??

azn akira 02-04-08 02:55 PM

i went with speed ventures

justint5387 02-04-08 04:06 PM


Originally Posted by azn akira (Post 7826257)
i went with speed ventures

Was it raining? I was going to go...

Silkworm 02-04-08 04:12 PM

yeah, you'll need to work on your exhaust for your next trip, if they suspect you're lifting for the sound meter you'll get the same warning.

Best I ran was a 1.55 with the 7, with a supertrapp fully corked killing my power, haven't been back since, not worth the hassle.

justint5387 02-04-08 04:34 PM


Originally Posted by Silkworm (Post 7826599)
yeah, you'll need to work on your exhaust for your next trip, if they suspect you're lifting for the sound meter you'll get the same warning.

Best I ran was a 1.55 with the 7, with a supertrapp fully corked killing my power, haven't been back since, not worth the hassle.

I think Laguna Seca is more fun than Thunderhill and Infineon, I will make my car pass the sound test in order to drive there.

Silkworm 02-04-08 06:00 PM

You will or you have?

If you have, I'd love to hear what exhaust mods it took to do it and how much power you lost in the translation.

justint5387 02-04-08 06:57 PM


Originally Posted by Silkworm (Post 7827005)
You will or you have?

If you have, I'd love to hear what exhaust mods it took to do it and how much power you lost in the translation.

I haven't taken the 7 there yet, but it is way less than 92db. It is a 12A stockport with a modified carb and RB exhaust. I am going to put in a 13B 6-port, it will still run the RB exhaust, so I am pretty safe regarding to sound. The extra 5 HP from running a straight exhaust won't make me go that much faster.

John Magnuson 02-04-08 07:01 PM

In order to run my single turbo FD at Laguna Seca without getting sound flagged I basically run as much straight flow muffler as I can plus a turn out. This consists of two large magnaflow mufflers plus a resonator.

Don't forget the turnout! It's the most important part. It dropped me from 98db to under 92db alone.

FWIW it's worth the car didn't SOUND loud with this exhaust and I never would have guessed it was over 92db even without the turn out. The sounds meters HATE rotary motors. You may THINK you're under 92db but you'll be surprised!

azn akira 02-04-08 08:36 PM


Originally Posted by justint5387 (Post 7826584)
Was it raining? I was going to go...

it rained at the end of saturday and from what i heard all of sunday

SHPNOUT 02-04-08 10:28 PM

John, I'm with you on the sound meter........I was told 94db with the muffler and the turn down. It surprised me to be that low......

BTW.....my motor is ported runs non sequental hi flow twins .

DriveFast7 05-02-08 06:50 PM


Originally Posted by justint5387 (Post 7827225)
I haven't taken the 7 there yet, but it is way less than 92db. It is a 12A stockport with a modified carb and RB exhaust. I am going to put in a 13B 6-port, it will still run the RB exhaust, so I am pretty safe regarding to sound. The extra 5 HP from running a straight exhaust won't make me go that much faster.

My 1st gen 12a streetport dellorto carb and the complete RB road race exhaust system header, dual presilencers, primaflow muffler passed sound no prob at Laguna.

That RB primaflow rear muffler really quiets things down, but makes the motor rev a up slower than a MAGNAFLOW 2.5" straight in/out back there.

KhanArtisT 05-03-08 12:54 AM

lol, you guys are fast. I'm still trying to break 1:30 in my built Porsche 911 in Forza 2.

j9fd3s 05-05-08 06:20 PM

couple random things....

some laptimes

schumachers 03 ferrari championship car, right out of the box (literally, they fed exed it), with the backup driver, ran 1.09's

shifter karts, run about 1.12's

917's/gt40's etc run in the 1.45 range.

dunno about fd's, its been 10years since i saw one run there.... anyone remember what alfinito was running?

NOISE:

we got the k2rd FC to do about 96db, it took an RB turbo back presilencer under the car. its 3" so no power loss. 92db you'd be running 2 of em, with a turn away.

i remember also that stock fd's didnt always make sound


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