C5 is a 1998 with a A4 trannie

Owner had Idaho Speed Center out of Boise install the mods below and custom DYNO tune it

Mods done :

CAM
INTAKE EXHAUST
VALVE ADJUSTMENT .000 .000
GROSS VALVE LIFT .525 .532
DURATION@
.006 TAPPET LIFT 269 273

VALVE TIMING OPEN CLOSE
@ .006 INT: 23 BTDC 66 ABDC
EXH 73 BBDC 20 ATDC
THESE SPECS ARE FOR CAM INSTALLED
@ 112.0 INTAKE CENTER LINE
INTAKE EXHAUST
DURATION @ .50 216 220
LOBE LIFT .3090 .3130
LOBE SEPARATION 114.0

LS1 1.75 Rocker Kit W / 5/16 guide plates
5/16 magnum pushrod 7.400
CS O-E "R" Series lifters
LS6 intake
Vararam cold air intake
X pipe
Header - no AIR and no rear 02 sensors
Borla exhaust from my X pipe to tips
Custom Dyno tune

End result of that shops tune and the morons ruined the front O2 sensors by unscrewing them while wiring was still connnected to main wiring harness and then again when installing them back when headers were installed which chokes off the air reference path in the wires

We then did a custom tune to clean the mess ( such as tuner had set WOT timing to 32 degrees, turned off torque management and stress control of the A4) up and from the OBD-2 Ease scanner data we were able to remotely find that there was this O2 issue and had owner replace them and rerun the car to see the end results.

2 common issues seen, with all the mods No ONE had considered that the stock injectors were too small which is seen with the test results below where fuel injector duty cycle was at 108% with 20 mSec pulse widths and this was in only 53 degree weather so in the heat of summer or on the drag strip engine would be even leaner then the 7% lean in todays weather

Second issue is the common BS that the Vararam is some hot cold air cleaner design when as we see in every case of this product as seen below that in 53 degree weather the average part throttle IAT was 14 deg hotter then weather and as high as 100 deg at low engine loads.

Add that even at 128 MPH the maximun airflow was only 38 lbs when best would have been about 42-44 lbs and that the maximum CFM was only 558 which is nowhere close to a stock 1998 MAF that can flow to 750 CFM

Overall the poor functioning of that Vararam restricts airflow and caused much hotter air into the engine which causes poor burns in the cylinders and only have larger injectors could overcome this but a better aircleaner CAI would reduce fuel needs.

Hey, never had heard that about Vararam cold air packages? I own a 1998 Corvette with an S&D LS2 based 402cid, with AFR 225 Pro Strip heads, long tubes, 3" X-pipe, B&Bs, Cam Motion cam 592 intake and 600exhaust lift, I also have a Vararam infront of the Magnuson 112. The car pulls hard (10:52-10:87 at 131-137mph) I do not know if you can feed an engine like mine with only 557cfms? Maybe it is the Magnuson? Don't know? Is your fit good? no major leaks? Have you contacted Vararam?

We in doing custom tuning have seen many Vettes that had underlying problems that all lead to that vararam over several years.

We have seen

1. cheap design for high profit margins.

2. as product gets older and due to engine bay temps the box gets out of square and unit allows hot dirty air to be pulling between the top of box and lower part.
Many times we have seen in customers cars the top has unlatched and owner did not even know it.

3. cheap foam filters that tear and come apart due to it being stressed between the top and lower part. After all the years this product has been out it is surprising to see the same aircleaner failures today as we did in 2003.

In fact once when we at a drag strip a C5 Z06 almost crashed as what we found later was part of the filter broke off, got caught in the throttlebody jamming the butterfly open

4. Random and airmass issues confusing the MAF and the PCM.

5. how this filter/CAI functions I can tell just by looking at a OBD scanner recording as the car listed in 1st post in this tread. Once seeing the ills via scanner data my 1st statement to owner was this car had a vararam ( remote tuning so I never saw the car) and he answered yes.

6. worse is the vendor sells the notion of more air / more performance but then sells the POS shown below that even the feds in the 1980s proved so called mods like this are useless that in fact reduce the air volume.
That junk part in fact did not even sit straight inside the airbridge and cause turbulance.

7. Vendor's marketing claims

Makes 40 + HP gains.
Reduces ET by 3.5 tenths
Increases trap speed in 1/4 mile by 3 MPH
Increases maximun speed by 8-10 MPH

If all that was done was adding their product my 40 years of racing says bullshit to their claims.

The front of car is designed for a good C/D and to help reduce lift thus there is no low airpressure so there is zero air being RAMMED in. To my viewpoint marketing it as varaRAM is misleading and if properly testing it and it alone in the real world on roads and it's claim of performance gains is BS.
What really increases the performance is the PCM tuning and not the aircleaner itself that would have very little gain seen at the real wheels.

As to the CFM, our 1999 C5 eats over 660 CFM and the engine is NA and uses a simple Donaldson Blackwing and our Icebox which prevents hot engine air entering the filter and takes in colder air from outside.


For the POS VR3 for $35 ( worth 2 bucks) below they make claims :

In Truck applications we have seen gains of up to 22+ ft/lbs of tire-shredding torque throughout the power curve where you can use it! As tested in a 2004 Silverado 5.3 V8.
In LS1 car applications, gains of up to 13 rear wheel HP have been seen (03 C5 Corvette).

Again my feeling, Bullshit

After owner had another shop replace the damper bolt ISC shop screwed up, replaced bolts missing in exhaust, replace the bad front 02 sensors, replace clock spring for airbag and steering wheel sensor we then had owner replace stock injectors with SVO 30s

After tweaking the tune and owner doing a relearn testdrive we see the torque came up nicely.

Customer says that vendor has folded up his shop but customer intends to sue vendor in small claims court for all the damage and costs to fix all the bard, lazy and non experienced work

I'd like to know what the outcome of the court case is.

C5 owner contacted me and said he has filed a small claims suit for about $3,000 in damages last week against ISC.

I hope he gets some money out of them.

We will see as the word is shop intends to go chapter 13

At least let's hope the Vette owner makes this public to the locals so they do not use a piss poor shop as this ISC is.

We hear several other vettes got wacked by that shop but the clue should have been that the shop worked mostly on riceball cars but went to a chevy dealership and a vette club and sold them how great they are but when a shop offers custom tuning for another $20 over chassis dyno costs you know
you get what you pay for

As to that Vararam crap, how many years does it take before the buying public learns those products are junk and do not belong on high performance cars