Discussion
I've just spoken to Peninsula and apparently my Griff that has had "one or two" mods done recently, put out 306BHP at the wheels which equates to 346 at the flywheel! Not sure what the torgue figure is, but meant to be an almost vertical line.
Can't wait to get it back on Thursday to give it a blast (it's been away for months as it was also getting resprayed).
How does the power compare to other modified Griffs?
Mine has got an ACT twin plenum, 404 cam, Mark Adams chip, ceramic coated manifolds, pre-cats removed & non-return cones.
Can't wait to get it back on Thursday to give it a blast (it's been away for months as it was also getting resprayed).
How does the power compare to other modified Griffs?
Mine has got an ACT twin plenum, 404 cam, Mark Adams chip, ceramic coated manifolds, pre-cats removed & non-return cones.
nice one grifftastic!!
mines is the same bar exhaust manifold / y piece, which are being done next week, so will be looking for similar results.
where was yours checked? power engineering seems to bethemost accurate place. mark reckons mines pushing 300 at the mo with 280 / 340lbft across the range.
most impressive thing is the continued power. used to get abit wheezy over 4000rpm...but with the cam & plenum, it jus keeps getting faster!!!!!!!!!
do you track it? would be interesting to get them out together
mines is the same bar exhaust manifold / y piece, which are being done next week, so will be looking for similar results.
where was yours checked? power engineering seems to bethemost accurate place. mark reckons mines pushing 300 at the mo with 280 / 340lbft across the range.
most impressive thing is the continued power. used to get abit wheezy over 4000rpm...but with the cam & plenum, it jus keeps getting faster!!!!!!!!!
do you track it? would be interesting to get them out together
Guillotine,
Totally agree about the twin plenum. When I got it done a few months back, it was like someone had cut the chains from the engine - it just wanted to rev and rev!
Richard at Peninsula reckons that the power now remains constant right up to 6200 rpm. Can't wait to give it some welly and definitely want to get on some TVR/TVRCC track days this year. Might start with a 1st Lotus session first, though!
Roll on Thursday. I don't know what will excite me the most; the power hike or the new paintwork and "bits". Had it resprayed Illusion Purple, so it's meant to colour shift from purple through blue into green. Also had quad pipes added with a sports type system mod. Oh, and had a mesh grill fitted instead of the spots, as I had already had the light conversion done.
One thing's for sure, you won't mistake me for someone else!!!!!
Totally agree about the twin plenum. When I got it done a few months back, it was like someone had cut the chains from the engine - it just wanted to rev and rev!
Richard at Peninsula reckons that the power now remains constant right up to 6200 rpm. Can't wait to give it some welly and definitely want to get on some TVR/TVRCC track days this year. Might start with a 1st Lotus session first, though!
Roll on Thursday. I don't know what will excite me the most; the power hike or the new paintwork and "bits". Had it resprayed Illusion Purple, so it's meant to colour shift from purple through blue into green. Also had quad pipes added with a sports type system mod. Oh, and had a mesh grill fitted instead of the spots, as I had already had the light conversion done.
One thing's for sure, you won't mistake me for someone else!!!!!
Calling all the experts out there!
It's interesting that some cars with the P404 and twin-plenum maintain power right up to 6,200 RPM where as mine runs out of puff at 5,400 - why is that likely to be?
I've got big injectors, so fueling shouldn't be a problem, and presumably air flow is the limiting factor? .... or something else!
Mark Adams suggested a different air meter, but also says that it would improve torque rather than power. My engine produces bucket-loads of torque as it stands, but I would like to see a bit more top-end...
Any ideas? Thanks.
It's interesting that some cars with the P404 and twin-plenum maintain power right up to 6,200 RPM where as mine runs out of puff at 5,400 - why is that likely to be?
I've got big injectors, so fueling shouldn't be a problem, and presumably air flow is the limiting factor? .... or something else!
Mark Adams suggested a different air meter, but also says that it would improve torque rather than power. My engine produces bucket-loads of torque as it stands, but I would like to see a bit more top-end...
Any ideas? Thanks.
Marlon said:
Calling all the experts out there!
It's interesting that some cars with the P404 and twin-plenum maintain power right up to 6,200 RPM where as mine runs out of puff at 5,400 - why is that likely to be?
I've got big injectors, so fueling shouldn't be a problem, and presumably air flow is the limiting factor? .... or something else!
Mark Adams suggested a different air meter, but also says that it would improve torque rather than power. My engine produces bucket-loads of torque as it stands, but I would like to see a bit more top-end...
Any ideas? Thanks.
Are those the standard injectors? You wouldn't normally need to change them unless you've had other changes made to the engine. If you've changed them you would have needed to change the fuel map to suit, and the person who did this is the best person to advise on the engine behaviour afterwards.
Could be the normal characteristic of the cam you've got, these are inherently torquey engines that don't rev as freely as many smaller engines. Could be you've got a worn cam and are losing valve lift. Could be just about anything out of spec in the induction system, or could be a fuelling fault. If you're still on the standard fuel map I remember Mark saying that the standard map runs lean at the top end and this probably wouldn't be helping.
Thanks Pete.
The injectors were recommended by Mark Adams and fitted by Power Engineering under his direction - I was apparently running out of injector duration at the top end - the induction system and cam (solid lifrer P404) was fitted by V8 Developments - and the car was twice fettled on the rolling road at Power Engineering by Mark Adams... all of the above was completed in July/August/September last year, so nothing should be worn and it has (I hope) been set up correctly.
Mark didn't give an explanation of why it wasn't revving past 5,400RPM - because I didn't ask, because I didn't expect it to - but it is curious that some cars get more at the top-end than mine.
I'll ask Mark Adams!
>> Edited by Marlon on Wednesday 21st January 16:16
The injectors were recommended by Mark Adams and fitted by Power Engineering under his direction - I was apparently running out of injector duration at the top end - the induction system and cam (solid lifrer P404) was fitted by V8 Developments - and the car was twice fettled on the rolling road at Power Engineering by Mark Adams... all of the above was completed in July/August/September last year, so nothing should be worn and it has (I hope) been set up correctly.
Mark didn't give an explanation of why it wasn't revving past 5,400RPM - because I didn't ask, because I didn't expect it to - but it is curious that some cars get more at the top-end than mine.
I'll ask Mark Adams!
>> Edited by Marlon on Wednesday 21st January 16:16
Check the fuel pump and filter! If the fuel demand from the injectors (standard or not) is too big you'll loose pressure, spray pattern and therby it will lean out and the power is gone. I don't know when a good pump with a new filter will start to drop pressure, but I'll check this out in a couple of weeks. Pete
Shirley if the mixture was leaning out due to fuel delivery it would show itself up on the RR 
.
Never understood this peak bit had mine re-done yesterday at Power with Mark and my peak has dropped from 6100 to 5700 rpm but increased in value 
, nowhere near your 346 though affraid I'm about 1000cc short too 
.
I'd be interested to know whats going on with peaks though.
Harry
. Never understood this peak bit
had mine re-done yesterday at Power with Mark and my peak has dropped from 6100 to 5700 rpm but increased in value , nowhere near your 346 though affraid I'm about 1000cc short too . I'd be interested to know whats going on with peaks though
. Harry
Marlon said:
...It's interesting that some cars with the P404 and twin-plenum maintain power right up to 6,200 RPM where as mine runs out of puff at 5,400 - why is that likely to be?
....
Been thinking a bit about this, see my earlier post about mine. One possible explanation is that the calibration, normally done at 60mph/revs is used to provide the scaling for the of the revs axis AFAIK. If you put a higher rpm for 60mph then it will shif the graph left.
If it was done on a RR near 'Theif-row' then they have the records on file and maybe able to extract the rpm/mph figure used. Anyone care to say what the gearing normally is
. For mine it is very close to 3000rpm for 60mph (rover box), I'm sure 3200rpm was put in. As I said previously my peak has dropped down the rev band by 400rpm, now that wouldn't normally be an issue but I have had 'power runs' on another RR not long before and it deffo peaked at 6071rpm. Also when the engine was built I had it bench dyno'd and it went to 6K and was still climbing.
This leads me to think the above is one possible explaination for the lower than expected rpm figure in my case because applying a correction to mine for the difference in 60mph ratio's of 3K2 to 3K puts the peak back to 6K1 which is where I expect it to be.
Right on the phone tomorrow.......
Harry
PS AIMHO and only one mans theory giving one possible explanation as to why the graph shows a lower than expected rpm/peak power curve. Could just as easily be the true figure
>> Edited by HarryW on Thursday 22 January 01:09
pvapour,
I'm sure that there will be more powerful Griffs out there, after all, there's always the 5.3 up-grade. According to Richard, the big plus with mine is the linear torque curve, but until I drive it (today!!), I won't really know.
Reckon I'll have to put a stop to the mods for now, as it has cost a small fortune!
I'm sure that there will be more powerful Griffs out there, after all, there's always the 5.3 up-grade. According to Richard, the big plus with mine is the linear torque curve, but until I drive it (today!!), I won't really know.
Reckon I'll have to put a stop to the mods for now, as it has cost a small fortune!
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