Are u sure the M-Speed NSR is the full blown modified version? Cause that one list for 69800-yen in Japan, roughly equals to US$650- and that's before sales tax. The full blown conversion have all the bells and whistles, even their latest M shape porting.

this is where i get the engines from:
www.racefactoryrcp.com

i thought that mike reade from model motorsports was the importer of Novarossi/ JP??

I just need some advise about my IDM 21P01 engine. I am having the issue that at the end of a long straight and sweeper comming into a hairpin at my track i release the throttle and when i come back on the throttle the car will just huff and puff and go no where for a second before it picks up again. Now it happens no where else on the track and i have tried to tune this out but havent had any success, it has been this way since new. I also have a much cheaper standard novarossi RX221PS and i have never had any sort of similar issue with this engine. Its a bit of a pain because im getting much better lap times out of an engine that costs almost half as much. I have never been all that impressed with the pace of my IDM compared to similar prices JP's.

Try with a larger line between your exhaust pipe and your fueltank, or try a different fueltankcap(?) with a "chamber" in it......

tuned pipe too short. try different-longer pipe.
edward

I had the same problem a week or two ago. I have the same track layout as you discribe. I solved it bij richening the needle for pick up. One of The serpent motorguyes said immediatly when he heard it, come to the pit, your low speed is to lean. Never had the problem again.
I think it has to do with somekind of vaporlock.

I have a few of them since they are dead cheap now since Ielasi switched to Picco.

They are regular N12LS3 engine and no, they are NOT modified. I measured crank and sleeve timings and compared to a stock LS3 = THE SAME.

But they are nice engines though, pretty fast and after I worked the crank (TopGun's way), one of them became killer fast