The Griffith Pages - THERE HERE! V8 ENHANCEMENTS TUNED MANIFOLDS

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THERE HERE! V8 ENHANCEMENTS TUNED MANIFOLDS

This is one of the most exciting after market modifications that has come out for the TVR V8 engine in a long time

Clive of V8 enhancements is pleased to announce his latest development for Rover v8 powered TVR`s.
The V8 Enhancements stainless steel tuned exhaust manifold system is a new application of exhaust tuning the likes of which (to the best of our knowledge) have never been seen on a RV8 powered TVR before.

Made from grade 304 stainless steel, and gas purged Tig welded, with a polished finish, these manifolds are a sight to behold in the engine bay, and to our knowledge give more performance than any other manifold system on the market for TVR Griffiths, Chimaeras and V8s.
Prices;
1 ½” primary pipes system…………. £2200. + postage + vat.
1 ¾” primary pipes system…………...£2450. + postage + vat.
These systems are made to order, please call Clive for further details, 07793553602.

The Test Results.

The graphs below represent the testing carried out on a Griffith 500, the spec of the car for all tests being;

72mm plenum.
Smooth bore air intake pipe.
Twin air filter outlet.
Carbon trumpets.
Crower 50233 road/ race cam.
Crane high rev lifters.
Adjustable pushrods.

All testing was carried out at Track Car Solutions on Jool`s Dyno Dynamics Dynamometer.

GRAPH A

The RED line represents the car running the standard Lucas ECU, with standard AFM, with the standard TVR manifolds and main cat fitted .
( please note that the manifolds had already had the pre-cats removed from them, so the red line is approx 5bhp higher than if the car was running on a completely standard system).

The BLUE line represents the car still with the Lucas ECU fitted, but now has the tuned manifolds fitted.

The GREEN line represents the car now running on a KMS ECU with the distributor being replaced by coil packs, and the tuned manifolds fitted.

After the initial testing was complete, I then made another set of manifolds, but this time increasing the diameter of the tube used in the primary pipes from
1 ½” to 1 ¾”diameter, also before I fitted these to my car, I decided to retard the timing of the camshaft as the peak torque was now 380ft/lbs at 3850rpm, and peak rpm power was occurring a little early for my liking at 5000rpm, so with the timing retarded from 108 back to 111 degrees, I then fitted the 1 ¾” manifold system and returned to Track Car Solutions for more testing, the results of this can be seen on Graph B.

GRAPH B

The blue line showing the performance of the 1 ¾” primaries, and the red line showing the performance of the 1 ½” primaries.
(The two different size systems were swapped over and tested on the same day).
You can see that the cam timing adjustment now gives a peak bhp at 6000 rpm, and the torque is now around 340ft/lbs.
The difference between the two pipe sizes is 4bhp increase at the top of the rev range for the 1 ¾” primaries, but they lose bhp to the 1 ½” primaries in the mid range.

Technical Details.

The system has been designed to achieve equal spacings of the exhaust gas pulses within the secondary pipework by pairing together the pipes that fire an engine rotation apart , for example cylinder 1 fires then the crankshaft rotates a complete cycle before cylinder 6 fires.
This pair of primary pipes must be of equal length for the tuning to have best effect. Therefore, cylinder 2 is paired with cylinder 3, 8 with 5, 7 with 4 and then 6 with 1, so there are 8 primary pipes paired up to 4 secondary pipes, joining into 2 pipes with one of these coming from cylinders 2,3,5 and 8, and the other from 1,4,6 and 7 , then finally coming into one pipe and connecting to the main exhaust pipe.
After extensive testing on the dyno at Track Car Solutions, it is clear that the design of this system will return substancial increases in
torque and bhp right across the rev range.
Initial testing was carried out on a 500 Griffith running a Lucas ECU, and involved back to back testing against the standard TVR manifolds and catted Y piece, please note that the manifolds had already had the pre cats removed so gains over standard manifolds would be even greater. The results showed that the tuned manifolds gave an increase of 25 to 30 ft lbs of torque and 20bhp, however these increases were not so substantial over 4000rpm, which is due to the limitations of the Air Flow Meter and Lucas ECU not metering the fuel correctly and the subsequent lean mixture in this rev range was limiting the true potential of the new manifolds.
This situation could be addressed by either remapping the Lucas ecu with Mark Adams, This e-mail address is being protected from spam bots, you need JavaScript enabled to view it or by fitting an aftermarket ecu, in this case the later course was taken.

Remapping the ecu is preferred because this exhaust system is less restrictive and allows the exhaust gas pulses to scavenge the exhaust gases out of the cylinder after firing, therefore on the next firing of the cylinder a fresher mixture is drawn into the combustion chamber. It's because of this much more efficient scavenging of the combustion chamber that you have to remap because the combustion chamber conditions have changed.
A few weeks later with a kms ecu on the griff, Jools at Track Car Solutions had the car on the dyno again to see how the manifolds performed with the new ecu and was pleased with the return of 323bhp and 378 ft/lbs of torque.
These results can be seen on the dyno graphs above.

Fitting

Basically these manifolds can be fitted by a very competent home mechanic, but if you are not one of those, then it’s a job best left to someone like Jools at Track Car Solutions, he can then fit system into the car ( contact ), and if you are already running an aftermarket ecu, he can tweak the ecu mapping to achieve the best performance possible from the new system.
With regards to actually fitting these manifolds into the car there are changes that need to be made to the cooling system, but these may vary from model to model, Joos V8S for example just involved moving the swirlpot forward by 2”, whereas my 500 serp griff required the bottom rad to water pump hose to be moved to run on the outboard side of the chassis, and the aluminium pipe from the bottom of the swirlpot had to be extended so that the silicon hose had sufficient clearance away from the exhaust pipes.
A pre serp engine may also require similar changes, as may the Chimaera`s, more details will be added about this at a later date.
At present, this system may not fit cars with power assisted steering, due to the position of the steering pump within the front chassis area which is where all of the secondary manifold pipes need to sit, however, I have carefully checked a Griffith with powered steering and feel that with a little re routing of the copper pipes entering the steering rack will allow this system to fit.

If this system if fitted to a car running the Lucas ecu, the wiring to the fuel injectors will need to be changed, this is because with the standard set up the left lambda sensor will read from cylinders 2,4,6 and 8, and the right 1,3,5,and 7, but with the new system the lambdas are in the pipes reading cylinders 2,3,5 and 8, and 1,4,6 and 7, therefore the wires going to injectors 4 and 6 need to be swapped over with those going to 3and 5 , this is easily done by making some wires long enough to reach from one side of the fuel rail to the other with some suitable connectors on each end, so that the wires feeding injectors 4 and 6 now feed 3 and 5, and vice versa.
This set up is not required for people running an aftermarket ecu with a wide band lambda sensor fitted into the exhaust, the boss for this being in the one pipe that connects to the cars exhaust pipe.

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