Dyno results

Hello guys,

This is still paul from paris ,france!
I got some results from my dyno man;
First ,after have changed the sparks ,regul the advance and change the seals of my holley it seems the car grow more fast in the rpm,and produce 188bhp NET which is much more different of the bhp GROSS!
The engine, after those "affinement" seems to produces 15 hp net more and less consumption...
The guy told me that before changing the sparks and reguling the holley ,the engine was lazy from 4000 to 5200,but now,he grows much more fastly in rpm...i ll confirm you that tomorrow!...i m so impatient to try my new christine!
A last thing,it seems the holley 600 is hard to regul,and give to much gas ,even with the f4b,what do you think about?

Hi Paul, it sounds like some significant progress was made! Please tell us again what engine size and modifications besides the 600 cfm Holley and F4B manifold you have. Is there an aftermarket cam, and do you have the stock exhaust manifolds or exhaust headers? The F4B should help with the inhaling side of the motor, but without headers and improved exhaling the better inhaling a F4B normally provides will significantly compromised.

The conventional wisdom seems to be that the 600 cfm carb is a bit too much for an essentially stock motor. The primary barrels are larger than those on a 465 cfm carb and thus with a smaller motor you get poorer mixture of the air and fuel because of the volume and vacuum of the air being pulled through it. Did your dyno man give you air fuel ratio numbers as part of him saying the carb is too big? Did he change any primary jets to try and get an optimal air fuel ratio? Any changing of when (what rpm) the secondaries open?

We would love to see the charts from the dyno runs! Cheers, Gene

Hello gene,

Thank again-after the alu rad/fan shroud(which are absolutely perfect) episode-for your response. You seems to be an unconturnable man in the tiger world...
Just to remind,my tiger is a 260,600 cfm ,f4b and edelbrock air filter.

So,i m gonna see the dyno man tomorrow(or tonight ;it s 1 o clock here..) but he told me today by phone that he first have changed the sparks i gave him (bosch dr7bc from brian postle). It seems it was a good thing,the old one were autolite,and were very dirty ,he told me.
After that and after changed the advance ,he put the car on dyno and have seen that at 4000 rpm the engine had difficulty to reach 5000-5200 rpm .
The floaters(?) of the holley were too high,so too much gas and the secondary didn t totally open. But there was too a lean of fuel so he dismantled the carb to change the seal,clean it(there was dirt),he had everything in stock(there was a incredible collection of genuine cobra,shelby 350,porsche 356 cab,even a real type e lightweight...incredible).
He has adjusted the jets but told me it was a little bit difficult because this carb -a remanufactured 600 cfm-non permitt a great possibility of adjustage(?).
Finally,he told me tonight he finally won 15 bhp on the last dyno today ,the compression were between 8,2:1 and 8,5:1,so quasi eguals,the combination between advance and air fuel mixture was perfect,,the engine reach the 5500 rpm without difficulty and he finallize that tomorrow morning in a last dyno run. He seems on the good way now the carb is clean.
I don t have new headers,but i m not sure it change so much,maybe on the last rpm...i think the carb is more important . Btw he has checked too the f4b seal,and everything is ok there.
I m gonna tell you much more tomorrow,i m gonna try christine and have all the detail of the curves(?) i m sure
she gonna be much evil than never!!
Thank you,gene

Hello guys

I got my "new" tiger after cleaning the carb,change his seals,the sparks ,the results are;
Ratio air-fuel:0.87 to 0,89 from 1500 to 5000 and 1,07 at 5500,the norm is 0.86 to 1,which is really good
A linear power on the graph from 1500 to 5500 and a final 188bhp net
torque is 211 at 3500 rpm,
before the modifications,there was a lost of power and torque at 4500 and bhp net was 169 and torque at 182 at 5500 rpm.

The more important seems that the power line is absolutly linear,without any lost,it seems my dyno man have made a good job!
BUT,when i took the car to go home,i made 40 miles and everytime i push hard the throttle the temp seems to rise more quickly than before...i don t know ,it s maybe the new sparks, but i think the carb is maybe a little too poor now

I ve a video -very impressive-of the dyno ,the two graph(before and after the modification)and a little graph of the compressions ( which are all the same) but i don t know how put them on the site .
The next step for me will be changing the steering,suspensions and tires,i ve bridgestone 205 r13 on mercury capri wheels ,i think 195 would be better...i ll see later...
Thank for you impressions and HAPPY TIGERING !
I love this car !

Paul

Hi Paul, thanks for sharing the results! Sounds like the F4B and Holley 4 barrel, plus the plugs and timing and tuneup gives some meaningful improvements. Those of us with a similar setup appreciate a fresh benchmark for comparison. BTW, the factory manual gives a stock rating of 136 net bhp at 4,200rpm and 226 lb./ft. net torque at 2,400 rpm. It also gives a Net BMEP torque of 131 Lb./ft. But I do not know how to relate that number to yours. Perhaps some other forum member can explain! Those factory numbers are of course with a two barrel carb on a low rise iron manifold.

How does the Holley respond after the tune-up, any stumbling or hesitation when you mash the throttle hard? I would suggest pulling one of the spark plugs after about 50 miles and check for coloration evidencing any lean carb condition if you suspect that might be happening.

What do you have in mind for the suspension upgrades?

Cheers, Gene

Hello gene

Again,thank for your response!

First of all,i m surprised too by the bhp level,but i imagine it can be explained by the 4 barrel,the f4b , the air filter(which is totally free...yes,i know...),new sparks ,a very good setup,and the results at 5500 rpm,which is a higher level than the workshop manual...
About torque,-i have the graph under the eyes-i just know the level i 200 at 2500,grow at 211 from 3500 to 4000 and start to fall slowly at 4200 to 5500 to finish at 190.
The start of the engine is instantaneous,and the power much more reactive and without any hesitation when i push the throttle. The temp rise more quickly until 170-180 when i push hard but fall quickly too(thank the new rad and shroud...). At least the engine "works" at a good temp...
I only feel the engine making soft misses when i stay a the same rpm without pushing hard the throttle,i think it s the delco,i maybe gonna change for a mallory.
About suspensions,i don t know. I think koni,but the problem are the rear left tire which sometime touch the arch and that i feel the direction too heavy(the engine?the tires?both?),maybe parallelism,that will be the next step. I ve seen dale s restorations which seem to be great work ...
If you have any advices...

Again,thank you ,and sorry for my un-terminable posts ,but you us guys are the only ones i can seriously talk about ours "christine"!
Cheers

Paul

Dyno Q

Paul

Thank you for posting without end

My questions:

The "Dyno" was a chassis Dyno reading HP and Torque at the rear wheels?

Are your figures of HP and Torque adjusted for friction losses? Typically estimated at 15% at the rear (driven) wheels? ( 100 engine HP = 85 rear wheel HP) (214 engine HP = 188 rear wheel HP)

Can you scan the graphs you have and post them here also?

Rick

hello rick

yes the dyno was on the rear wheels and i don t think there is a friction lost on the graphs.
I didn t assist the runs because i was at work but the dyno man made a one minute film i can send you if you give me your mail.
For the graphs,I only have an i-phone and i can try to put them on this site next week ,i m in holidays next friday and i go to my father home,he got a computer.
What do you think about the numbers mesured?
Cheers

Paul