GTech Pro RR in C3s
Thread Starter
Instructor
Joined: Jun 2006
Posts: 123
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From: Westminster MD
GTech Pro RR in C3s
Anyone using a GTech Pro RR with a C3? I'm interested in a performance meter for measuring tuning changes and for the occasional autocross. I'm also wondering if the RPM feature works correctly with these old ignitions (very noisy).
Le Mans Master
Joined: May 2006
Posts: 9,993
Likes: 1,136
From: League City Tx
A buddy of mine track tested his G-tech pro in a 66 coupe. It was within 1 tenth on his 1/4 et but the mph was way off. I think he said it was repeatedly 3-4 mph fast reading compared to his traps at the strip.
I would say gave your money and just go to the dragstrip and REALLY see what it does.
I would say gave your money and just go to the dragstrip and REALLY see what it does.
Racer
Joined: Aug 2005
Posts: 315
Likes: 0
I agree,I bought the gtech pro RR last year and I was disappointed with it's results.
The RPM worked fine on it thought.I've never been at the track so it's pretty hard for me to compare.You will not be getting the results you want on HP 'cause it can't measure engine HP nor RWHP......It measures Net HP
80_vette
The RPM worked fine on it thought.I've never been at the track so it's pretty hard for me to compare.You will not be getting the results you want on HP 'cause it can't measure engine HP nor RWHP......It measures Net HP
80_vette
Team Owner
Joined: Jul 1999
Posts: 26,545
Likes: 46
From: Huntersville NC
A buddy of mine track tested his G-tech pro in a 66 coupe. It was within 1 tenth on his 1/4 et but the mph was way off. I think he said it was repeatedly 3-4 mph fast reading compared to his traps at the strip.
I would say gave your money and just go to the dragstrip and REALLY see what it does.
I would say gave your money and just go to the dragstrip and REALLY see what it does.
If what you are saying is the Gtech mph reading was 3-4 mph greater than his timeslip, then I would say everything was working properly! The Gtech calculates his exact speed at the moment he as traveled 1/4 mile (It doesn't even know where the finish line is, it just starts measuring when he starts moving, and calculates when he has gone 1/4 mile, and calculates the speed at that instant in time.) The track relies on mechanical devices, and his speed is calculated by 2 sets of lights that give you an average speed over the last (?? I forget how many feet) feet traveled at the dragstrip. So with most street cars you are still accelerating at the end of the 1/4 mile and your actual speed crossing the finish line will be greater than the average speed that the track prints on your timeslip.
Thread Starter
Instructor
Joined: Jun 2006
Posts: 123
Likes: 0
From: Westminster MD
I agree,I bought the gtech pro RR last year and I was disappointed with it's results.
The RPM worked fine on it thought.I've never been at the track so it's pretty hard for me to compare.You will not be getting the results you want on HP 'cause it can't measure engine HP nor RWHP......It measures Net HP
80_vette
The RPM worked fine on it thought.I've never been at the track so it's pretty hard for me to compare.You will not be getting the results you want on HP 'cause it can't measure engine HP nor RWHP......It measures Net HP
80_vette
.I’m mostly interested in changes in performance after tuning the carburetor and ignition. I’m thinking about replacing the carburetor also, if I do that I want to make sure the car is faster.
Racer
Joined: Aug 2005
Posts: 315
Likes: 0
The net versus gross HP is something I’m aware of, I figure if the net HP is embarrassingly low on my Corvette I’ll just run the GTech in my son’s Saturn and that will surely make me feel better .
I’m mostly interested in changes in performance after tuning the carburetor and ignition. I’m thinking about replacing the carburetor also, if I do that I want to make sure the car is faster.
.I’m mostly interested in changes in performance after tuning the carburetor and ignition. I’m thinking about replacing the carburetor also, if I do that I want to make sure the car is faster.
Regards
80_vette
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Thread Starter
Instructor
Joined: Jun 2006
Posts: 123
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From: Westminster MD
, so if I get one I’ll let you know how it works.
Drifting
Joined: Dec 2004
Posts: 1,345
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If what you are saying is the Gtech mph reading was 3-4 mph greater than his timeslip, then I would say everything was working properly! The Gtech calculates his exact speed at the moment he as traveled 1/4 mile (It doesn't even know where the finish line is, it just starts measuring when he starts moving, and calculates when he has gone 1/4 mile, and calculates the speed at that instant in time.) The track relies on mechanical devices, and his speed is calculated by 2 sets of lights that give you an average speed over the last (?? I forget how many feet) feet traveled at the dragstrip. So with most street cars you are still accelerating at the end of the 1/4 mile and your actual speed crossing the finish line will be greater than the average speed that the track prints on your timeslip.
The G-tech measures RWHP. I have tested about 20 different cars with the original G-tech and it is VERY consistent. Some numbers for reference based on MEASURED weights:
'63 Fully Stock 327-300 HP Gross 165 RWHP
'69 Fully Stock 350-300 HP Gross 170 RWHP
'93 Fully Stock 350-300 HP Net 195 RWHP
Fully Stock 350-375 HP Net 313 RWHP (DOHC)
'01 Lightly Modded 350-350 HP Net 274 RWHP
'69 Highly Modded 350 320 RWHP
'69 L-88 Replica 427 345 RWHP
'04 Viper SRT-10 414 RWHP
I have also done some non sports cars:
'02 6.0l Chevy Truck 300 HP Net 195 RWHP
5 cyl 270 HP Net 180 RWHP
(3 different trucks tested all within +/- 3 HP)
'68 Low CR 327-275 HP Gross 135 RWHP
'97 Neon DOHC 122-150 Net HP 125 FWHP
'63 Aluminum Buick 215-200 HP Gross 145 RWHP (Modded)
Melting Slicks
Joined: Dec 1999
Posts: 2,116
Likes: 156
From: Mid West
Cruise-In III Veteran
If what you are saying is the Gtech mph reading was 3-4 mph greater than his timeslip, then I would say everything was working properly! The Gtech calculates his exact speed at the moment he as traveled 1/4 mile (It doesn't even know where the finish line is, it just starts measuring when he starts moving, and calculates when he has gone 1/4 mile, and calculates the speed at that instant in time.) The track relies on mechanical devices, and his speed is calculated by 2 sets of lights that give you an average speed over the last (?? I forget how many feet) feet traveled at the dragstrip. So with most street cars you are still accelerating at the end of the 1/4 mile and your actual speed crossing the finish line will be greater than the average speed that the track prints on your timeslip.
I based lined my Gtech pro (not the RR version) against a V6 mustang I had when I purchased it. When it calculated the RWHP, it was exactly where the factory said it should be assuming a 15% driveline loss. I was quite impressed. Also, I agree it should report a slightly higher MPH at the dragstrip due to what was mentioned previously. It's not as good as a dyno, but I was pleasently suprised by it.
Race Director
Joined: Apr 1999
Posts: 11,520
Likes: 13
From: CORVETTE 77 385 C.I. TEXAS
MPH will not match drag strip nos.
Assuming it is consistant, even if it not exactly accurate, it would still work to measure improvements if used consistantly under the same conditions.
Assuming it is consistant, even if it not exactly accurate, it would still work to measure improvements if used consistantly under the same conditions.