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Group Buy Prospeed Hi-flow Cats and ECU Rom tune service Combo Group Buy!

3 August 2006
The OC
PROSPEED Hi-Flow Catalytic Converters and ECU ROM Tune Service Group Buy!

This is a:
[X] Direct vendor group buy

Minimum Number of Units :3 sets

Maximum Number of Units :10 sets

Closing Date : 30 Days from today 4/11/2010

Product Will Ship: [X] After the group buy is closed

Payment Procedure: [X] Payment in full upon signing up

Payment Methods Accepted : Paypal please add 3% for paypal fees. PM me for paypal email address.

Estimated Delivery Time / Date: All items will ship by no later then 4/22/2010

Product Pricing : Participants- 3 = $749 shipped / 4-10 = $699 shipped. to all 48 states. Additional cost elsewhere.

Signup List :


Product Info, Photos, etc.:

PROSPEED Hi-Flow Cats!

The Prospeed Hi-flow Cats will be a direct bolt on replacement for your OEM cats or Test pipe. They is a great chance to upgrade your old 17 year old clogged cats and not only make more horsepower but lose weight from the OEM cats. The OEM cats are extremely expensive at a little over $2000+ for the pair so this is a great alternative over the OEM cats. The Prospeed Hi-Flow Cats will also pass 48 state emissions for all OBD-1 NSX's 300 cell versions will pass CA emissions. Testing for OBDII will be done shortly after completion of the 95-99 year cats.

- We offer 200 SS cell cores that flow 400+ CFM
- We offer 300 cell cores and 400 cells cores to help with passing emissions.
- Full high flow metal substrate cores
- Tubing are high grade 304 Stainless Steel
- All pipes are 2.25" to match properly to your aftermarket headers and exhaust
- Fully TIG welded and tested to fit
- Flanges are laser cut for proper fitment
- Comes complete with gaskets and Hi Grade bolts, nuts and washers
- Light weight design
- Advantages of a test pipe without the smell, raspy sound and the black bumpers
- Low cost, OEM cats retail for over $2000+
- Bolt on, no welding involved
- Completely Made In The USA
- Go Green! Get rid of your test pipe and save the planet!
- OBD II EPA Compliant for 48 states. (Also EURO III Compliant)
- Confirmed to pass smog in Ca for both OBD I and OBD II NSX's

-91-94 NSX
-95-99 NSX
-00-05 NSX

-custom flanges for 97+ headers on 91-96 NSX.

-95-99 (7/3/08) Currently in production.
-00-05 (TBA)

Normal Price:
91-94 - $575
95-99 - $549
00-05 - $549





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We finally had time to get the test mule on the dyno. We were pleased with the final results after adding on the Prospeed Hi-Flow Cats. The higher flowing cats really showed itself down low with an increase in torque of up to 5 ft lbs of torque at a usable 4000 rpm. We made our most torque and HP ever at 267.5 HP and 205.12 ft lbs. of torque. The only change was the Prospeed Hi-flow Cats. No fuel or ignition timing was done to the car. I am personally happy with the upgrade. Increase HP, lighter weight then OEM cat (approx. 12-13 lbs savings) and a nice deep "growling" sound exhaust. We will be testing out the 95-99 soon. We believe the restriction is greater on the later model NSX's due to the diameter of the opening on the OEM cats. check out the results below...




Dyno: Dynapak dynometer (Thanks to Bisi from Bisimoto engineering for using the facility)

The car has about 65,XXX miles on it (1991 NSX, 5 speed)
Mods- Stock airbox with comptech filter, Taitec GTLW exhaust, Top Speed Headers, Prospeed Stage 3 Rom Chip and Prospeed Hi-Flow Cats.

NOTE: We compared our most recent hp from the last time we dynoed on the 28th of MAY to our dyno with the Prospeed Hi-Flow Cats on the 22nd of July. Both runs were done SAE corrected to eliminate variables. Also on may 28th temps. were 78 degrees F. vs 98 degrees F. on July 22nd.



Blue dotted line indicates run with comptech filter, taitec GTLW exhaust, Top Speed Headers, and Prospeed Rom Stage 3.

Blue solid line indicates run with comptech filter, taitec GTLW exhaust, Top Speed Headers, Prospeed Rom Stage 3 and Prospeed Hi-Flow Cats.

-Peak 267.5 HP with 205.12ft lbs of torque
-As you can see we picked up around 2 hp to 5 hp Throughout the power band. 5 hp at 7280rpm.
-The NSX saw excellent gains in torque gain from 2ft lbs of torque to 5ft lbs of torque.
-Torque can be felt from around 2000 to 4500 rpm.
-Noticeable increase in throttle response.
-Slightly louder then the stock OEM cats but doesn't drone or have that raspy sound normally associated with test pipes.
-Part throttle driving and cruising still remains fairly quiet. Increase in decibels when you floor it.
-12-13 lbs weight savings over OEM cat.
-Greener then a test pipe and no stinky smell or black bumpers!
-Higher flow cat will be great for forced induction applications. Perfect for the Comptech supercharger owners.[/QUOTE]



It is finally here after 10 months of development and hours and hours on the dyno we are offer dyno proven ecu upgrades for the 91 to 94 NSX. Auto and Manual.

Here are the stages-

stage 1 basic/filter and exhaust only 8 to 12 HP 8-15 lbs of torque

stage 2 intake/filter, header, exhaust 10-17 hp 10-18 lbs of torque <--- our most popular Rom.

stage 3 custom ROM tune for N/A application 10-20+ hp depending on compression and mods

stage 4 is available for local NSX owners in the so Cali area. Includes custom tuned ROM specifically for their mods. Dyno tuning is $150 an hour.

We are in development for boost applications.


What was involved in the development included tuning on a dynojet dyno with a wide band O2 sensor.
We tuned fuel and ignition timing including part throttle tuning to improve throttle response and retain your original gas mileage. We also adjust vtec and rev-limit according to the application. It will also pass smog if the vehicle pass smog before.

This by far superior to any chip that is available for the NSX market. Many "chips" on the market are one off chips with not much dyno testing. Most people haven't even dynoed their cars before and after the ecu mod to really know if it helped. We spent a lot of time on developing this and we believe it will help out our community.


Dyno: Dynojet

The car has about 62,XXX miles on it
Mods- Stock airbox with comptech filter, Taitec GTLW exhaust, Top Speed Headers, Prospeed Stage 2 Rom Chip.

Note: We forgot to delete the older text that says "prospeed chip version 2" and "Airfilter with 3.5 velocity stack" We did some extra tuning with it and made the same hp so we kept the existing OEM airbox.



Blue line indicates run with only comptech filter, taitec GTLW exhaust, and Top Speed Headers.

Purple line indicated run with comptech filter, taitec GTLW exhaust, Top Speed Headers, and Prospeed Rom Stage 2

-Peak 270 HP with 204ft lbs of torque
-As you can see we picked up around 8 hp to 14 hp Throughout the powerband. 11hp at 7000rpm.
-The NSX saw excellent gains in torque gain from 8ft lbs of torque to 15ft lbs of torque.
-I was impressed with the torque from around 3000 to 5000 as we gain around 15ft lbs of torque throughout. All in all i was able to squeeze a little more power and smooth out the graph. I personally feel it was worth the extra time on the dyno.
-Noticeable power increase.

The results speak for themselves.
- 8-12 wheel hp between 3000-6500 RPM.
- 10-15 ft/lb torque increase between 2800-6500 RPM.
- Flat and smooth power band throughout.
- vtec lowered to 5600 rpm.
- rev-limit raised to 8200 rpm.
- TCS fully functional
- Fuel economy unchanged

What is included in our Rom Tune Service?

Prospeed ROM tuned ecu chip, zif socket and installation. Ecu needs to be sent to us. The ecu needs to be sent to us for prepping and installation. For $25 more we offer next day air back to you in the Continental US. We will return the ecu in perfect running condition including your original OEM chip.


-NORMAL PRICE Stage 1 and Stage 2 Now Just $349 This includes free installation and free ground shipping. Next day air is an additional $25.

-We also offer custom rev limits either 8000rpm or 8200 rpm rev limits.

-Please look at the testimony in this thread from the many happy NSX members with our Stage 1 or 2 Rom Tune and decide if it is right for you!

We stand by our product and guarantee hp increase.
please contact me by PM
Last edited:
Groupbuy is closed! Thanks guys! I will have it out to you asap!

If you guys want to get the high polish look guys PM me and ill have them done before shipping out! Heres more info


We are introducing a new line of high end Prospeed cats for the NSX.

PROSPEED PRESTIGE High Performance Catalytic Converters!!

The Prospeed Prestige line will come standard with our top of the line 200 cell core catalytic converters and is 100% fully polished and give that long lasting high end look you expect for your NSX. This is the best and only production 200 cell Hi-flow cats for the NSX. Perfect for those with a CTSC or SOS hi-boost superchargers.

The cost is $675 for the pair.

If you wish to have just the long lasting high polish look it will be an additional $45 to the cost of the standard 300 cell Prospeed Hi-flow cats. Well worth it! They're stunning in person. PM me for more information on this service.

Hi Brian, you seemed to have gotten all your act together finally. Congratulations!