11 replies to this topic

[bigfish]

  I am just wondering if it is realistic for a 1275 to make 90 - 100hp  with "some"  street manners,  and a useable rpm range.rpm.   1990 1275 a+  stock bottom end driven only for fun and on weekends.  And what is that proven combination to make that power utilizing hif 44.    will cam , head and increased compression ratio do it?   I am new to the small cubic inch mini motor and are really wondering what can be obtained with these motors..   .

                                                                                                                                                   

[AlexMozza]

Fitting a new cam, bigger bore and serious head work could see around that Mark.

[Broomer]

No.

[ACDodd]

It is perfectly possible nowadays with perfect smooth idle. Well, 97 to 99hp anyway! However it will be hard on the valve train as the spec uses 1.5 rockers. I have a few cars dynoed now using my ACD - RS cam and consistent 97 to 99bhp and between 92 and 97lbft of torque. None of these engines were built by me they were dynoed at Slark race engineering. Although I don't recommend high 1.5 rockers with my road cams due to increased wear issues, they do add a chunk of grunt (worth about 10 to 12hp on the RS grind.


Ac

Edited by ACDodd, 21 July 2016 - 06:54 AM.

[Fast Ivan]

Yes, start with the cam selection - take a look at one of AC Dodds. Pretty sure it was his RS cam, together with a Calver head and twin Su made close to 100 bhp. I think it was also bored out to 1330.
I do not have the specs to hand but I know you won't need to rev the nuts off it and the idle is good, maybe slightly lumpy

[robminibcy]

what about looking down the forced induction route as well? Or maybe better still a 16v cylinder head conversion from specialist components or the like?

Edited by robminibcy, 20 July 2016 - 10:11 PM.

[Dusky]

Vizard seems to love the 544 for the road.
On his tests engines with that cam make around 100bhp.

[ACDodd]

Here you go,544 cant match that torque at 2k rpm!!

Attached Files

•  FB_20160720_23_12_27_Saved_Picture.jpg   29.95K   119 downloads

Edited by ACDodd, 20 July 2016 - 10:19 PM.

[nicklouse]

Why give a bhp figure? It is pointless on a road car. Build an engine with bags of torque as that is what gets you in the small of your back and gets you to 60 quick.

[Earwax]

Fat torque curve, and slightly shorter final drive,,,,, doesn't matter if it is, 75, 95 hp, it will give you a grin..... IMO whilst a number of race type cams from early times are still highly regarded, i think more modern cams for road cars are less lazy,have  more torque available where it matters ( tuned for the appropriate rev range) and have been developed with less need for big big ports ( exhaust especially).. and therefore a better bet.   Again i like to see torque graphs of an engine, bearing in mind it is the whole build that combines,  and as an example, why sometimes going to 1.5 ratio rockers is a step backwards,.. So find a good head porter and they usually will make or influence the grind of a good set of cams.

 

NOTE  I deliberately didn't go into specific cams  and i haven';t tested or experienced lots of them... but to avoid blurting stuff out withoutbacking it up, i would suggest the AC dODD cams, the Kent cams where swiftune have influenced the grind,  the Graham Russell/ Calver cams , and probably more are all capable of a streetable 95 plus HP motor,

 

Enjoy the build!! but don't get hung up on a figure.... it may well be cheaper in $ per HP gained to switch to a lithium battery and go on a diet.. but where is the fun in that

[Fast Ivan]

AC Dodd RS Cam in the red, 248 degrees duration compared with the 270 of the other cam

[Dusky]

Now is it a 544 or a 276?