The V8 Owners Forum -

Tricky is using huggers Kev!
He knows he has to get some bigger pipeage in there. But he has to figure out how first eh Rich

I can see a real special custom exhaust appearing on the car next year! Cos he doesn't have much room to play with.

From My Vizard Otto cycle efficiency graph going from 7:1 to 11:1 would increase power from 276BHP to 310BHP - all things being ideal.

Going to the more typical 9.75:1 would increase power to 301

Andrew

mgbv8 wrote:Tricky is using huggers Kev!
He knows he has to get some bigger pipeage in there. But he has to figure out how first eh Rich

I can see a real special custom exhaust appearing on the car next year! Cos he doesn't have much room to play with.

Perry,

I was just confirming what others had said about how restrictive block huggers are, the problem with the TR7 shell is obviously the strut towers being in the way of MG RV8 type headers..

Kevin.

Looks like its going to be 8 pipes out of the bonnet for race days eh!!

I am having a new exhaust system built at mo but wont be ready for Retro show so much to do before show
We think with some hard work we can get 2" primaries in what do you all think am i trying to go to big?
I must add my Tr, sat in my workshop for allmost 5 years its great to have her back again so at the mo i dont want to strip her again, am trying to make the best of what ive got i dont have unlimted funds

Tricky,

The cam you mention as a Mechanical 256 are you saying that it is a Kent M256 as I assumed in an earlier post.

Your dyno results do not reflect the characteristics of that cam so am wondering if you actually have something else.

I know that you have a very nice pair of full race heads which would compliment a fairly wild cam, but that cam would go flat at anything under approx 3000 RPM.

Also ran the figures through a dynamic compression calculator and if your static C/R is as low as 7/1 and with the Kent 256 valve periods then the dynamic C/R will be in the low fives and this does not seem to make sense, with the kent 256 you would need a static C/R of approaching 12/1

Did you build the engine yourself or do you know the piston bowl volume so a static C/R can be calculated?

Kevin.

Hi Kevin

I bought the the bottom end striped secondhand she had only run up the strip twice, i rebuilt the bottom end and fitted a Real Steel 256 mechanical cam i worked out the Cr from bore ,stroke piston dish ,head cc etc and it came out at 7:1
Ive written them down some were but do you think i can find them now
Ive always felt that a big cam in a big capacity rover helps soften the cam
if you get were am coming from
Ive been working on her today and may have found??? a problem the carb stud that holds the throttle cable has pulled its threads allowing the cable to close down to about 3/4 throttle
This may by why the power curve flattened out after after 3500 Rpm?

Hi,
Thats not going to help Tricky!
Its not nice trying to get a decent size of pipes into a TR7 bay everything seams to get in the way As for the pre made so called TR8 pipes they only fit where they touch!!
Still cant wait to see your car in a couple of weeks ( and you other gents cars of course )
Cheers John

Tricky,

The real steel 256 looks even hairier then the Kent 256, what RPM does it run cleanly from, and where does the power start at, and whats your rev limit as Real Steel quote a power band of 4000-7400 RPM but that may be a lower rpm with a bigger 5L engine.

Have you upgraded the valve gear to handle the higher RPM, I'd recommend fitting the outrigger end pedestals as a minimum if you haven't already done it as the very high lift of that cam is going to put a lot of stress on the rocker gear.

The heads and the cam should work very well together on track and the potential to produce more power is clearly there.

I was more concerned about the lack of compression and how much power thats costing you but there's not a lot you can do about that with the pistons you have, but that does leave you with the further potential of forced induction at a later date but you would need to change the cam for a suitable blower one.

Have fun.

Kevin.

She starts to pull clean about 3000 i am running roller rockers with Chevy style oil hole push rods
These are the figures from rolling road sorry cant up load dont have scanner
Max power 276.1 at 5200 rpm
she was making 220 at 3300
Torque 342 ftlbs at 3150
and 320 at 2250

Tricky

For info
The GT40s at Le Mans in 1968 / 1969 used 1.5 inch primaries on their 5 litre engines said to develop about 450 hp

Possibly going too far at 2 inch

Ian

Tricky wrote:She starts to pull clean about 3000 i am running roller rockers with Chevy style oil hole push rods
These are the figures from rolling road sorry cant up load dont have scanner
Max power 276.1 at 5200 rpm
she was making 220 at 3300
Torque 342 ftlbs at 3150
and 320 at 2250

Tricky,

Obviously plenty of power in a relatively lightweight car, what surpises me is that R/S say the cam has a rev range from 4000-7400 so would have assumed peak torque would be around 5000 RPM and peak BHP around 6700 RPM, your apparently peaking a lot lower unless you didn't get anywhere near full throttle in which case there may be more to come

Kevin.

Hi all been working on my Tr all week and the list of jobs to do is not getting any smaller

A very big thank you to Perry for getting my Nos bottles filled up

At this moment in time i still have the following to complete before next weekend SOMEHOW

Fit Nos system and street max controller
change all suspension rear bushes
replace gearbox remote bushes
Replace alternator just decided to pack up
Sort out driver seat and belt
Replace exhaust rear mountings
Change throttle cable
Close off rear deck panel due to stripping interior
Change gearbox oil
Change rear tyres
Adjust wheel alignment
Check over cooling system lost some coolant
Change position of line lock

Off to workshop tomorrow again will be at Santa Pod Saturday as camping over some how

Looking forward to weekend and meeting all that are coming

not much to do then,what will you be doing the rest of the week ,see you on saturday, rich

Sleeping i hope see you at Santa Pod Rich