DYNO of Mike's regrinds

[naprotejay]

Very interesting/surprising results!

Same basic setup as last time: 224K mile original motor, 87 octane, 14 degree timing all runs listed. outside temp ~8 degrees cooler than last time...

2) baseline with intake cam -1, exhaust cam 0:

116.5 whp/ 107.1 ftlbs

the torque *peak* is misleading: i gained 10 ftlbs below torque peak!!(i'll be more specific below)

3) intake cam(INT) 0, exhaust cam(EXH) 0:

117.6 whp/ 108.8 ftlbs

5) *** INT +2, EXH 0: ***

*** 117.3 whp/ 110.5 ftlbs ***

w/RX7 VAF richened 2 clicks:

*** 118.3 whp/ 111.1 ft lbs ***


now comparing this to my best previous peak torque with the stock INT +4, EXH 0 (116.1 whp/ 108.7ftlbs), i gained ~15 ftlbs @ 2600 and 3000rpm!! from 3250 to 4500 the gains gradually taper from +5ftlbs gain to +3ftlbs @ 4500. fat torque gains to 4700rpm where the stock cams finally (nearly) match the regrinds. peak gains 2hp as well.

9) INT -2, EXH 0:

119.8 whp/ 109.8 ftlbs

10) *** INT -3, EXH 0: ***

*** 120.6 whp/ 109.8 ftlbs ***

w/RX7 VAF richened 2 clicks:

*** 121.1 whp/ 109.9 ftlbs ***

comparing this to the best previous peak hp (WHEN retarding the INT...) with the stock INT -4, EXH 0 (116.0 whp/ 108.5 ftlbs), i gained 5 whp @ 6650 rpm with the gains growing all the way from 5400 to redline! @ 5700 the regrinds begin making about +3whp over the stock cams. there are torque gains as well with +13ftlbs @ 2750 to 3000rpm. +4ftlbs from 3700 to 4000.

those are the best of the runs - spent 2hrs on the dynojet doing 20 4th gear pulls.

basically i went from 0 to +6 and 0 to -6 in 1 degree increments on the intake cam. once i found the 2 best settings noted above ( #5 and #10), i then adjusted the RX7 VAF. interestingly enough both of those cam settings liked it 2 clicks richer over the original setting with the stock cams.

the last run #20 i set the INT +2, EXH -2 (ignition set to 14):

118.8 whp/ 110.5 ftlbs

what's interesting about this last run is how ABSOLUTELY SMOOTH the power is! in other words, NO 'choppiness' - like some of the other runs tend to have... the motor had been thoroughly wrung out by then too.

[MazdaRacer]

Good stuff Jason....the cooling system took some abuse huh...LOL

I definetly like the +15ftlbs at 2600-3000!!!!

[naprotejay]

that's exactly what was so surprising to me - but it now makes sense as the motor has seemed so much more responsive at lower rpms since the install...

now PLEASE somebody who has the bolt-on's and the stock 1st gen DC install these and dyno before/after!! who knows maybe you'll make more power than i did! i definitely would like to see what someone else dynos at to verify gains.

[mike323]

that's exactly what was so surprising to me - but it now makes sense as the motor has seemed so much more responsive at lower rpms since the install...

now PLEASE somebody who has the bolt-on's and the stock 1st gen DC install these and dyno before/after!! who knows maybe you'll make more power than i did! i definitely would like to see what someone else dynos at to verify gains.

Did you advance or retard the intake/exhaust cam by 8 degrees or more? All this gain in lower torque should be shifted in the upper rpm range in order to reach 130+ whp. To do this the adj. cam gears needed to be advanced(clockwise) +8 or more on the intake cam and the exhaust retarded(counter-clockwise) several degrees to increase the overlap.

[naprotejay]

Mike, i went to INT +6, EXH 0 . made 113.8 whp/107.7 ftlbs and the car was really 'loping'. since we didn't gain anything over the INT +2 (tried +3 and +4 as well), we decided to see what would happen when retarding....

i also wondered if perhaps the TDC cam timing was a little off. as you said before, the 4.5 teeth clockwise from the exhaust slot is not exact..... the last run where i did INT +2, EXH -2 got me thinking that maybe i should try that setting and work from there..... its takes so much experimenting to figure out what is best!!
thanks for the regrinds! there's gotta be more peak power to be had....

[mike323]

Mike, i went to INT +6, EXH 0 . made 113.8 whp/107.7 ftlbs and the car was really 'loping'. since we didn't gain anything over the INT +2 (tried +3 and +4 as well), we decided to see what would happen when retarding....

i also wondered if perhaps the TDC cam timing was a little off. as you said before, the 4.5 teeth clockwise from the exhaust slot is not exact..... the last run where i did INT +2, EXH -2 got me thinking that maybe i should try that setting and work from there..... its takes so much experimenting to figure out what is best!!
thanks for the regrinds! there's gotta be more peak power to be had....

If you advance or retard the intake cam by too much you'll get a lopy idle. Advancing the intake increases the overlap and retard it by too much closes the intake valve later(this is good for top end but at low end reduces power).

Have you tried retarding the intake cam by 6-8 degrees and than playing with the exhaust timming?

Just so we can be on the same page, when you adjust the cam gear you rotate the camshaft and not the cam gear. 2 degrees on the cam gear/camshaft is 4 degrees on the crank. Rotating the int/exh cam clockwise is advancing, and couter-clockwise is retarding, since the timming belt rotates clockwise.

[naprotejay]

Have you tried retarding the intake cam by 6-8 degrees and than playing with the exhaust timming?

Just so we can be on the same page, when you adjust the cam gear you rotate the camshaft and not the cam gear. 2 degrees on the cam gear/camshaft is 4 degrees on the crank. Rotating the int/exh cam clockwise is advancing, and couter-clockwise is retarding, since the timming belt rotates clockwise.

not yet....

and correct - i loosen the the 5 nuts on my adjustables, rotate the camshaft to whatever retard/advance setting i want, and then tighten it back up.

here's what i've been thinking - instead of trying to find more high-end by playing with the adjustables with the cam timing as its currently set; it seems the more logical/consistent/faster way is to move the gear 1 whole tooth. in other words, right now @ TDC my intake gear might be 5 teeth clockwise from the exhaust slot. or it may be 4 teeth... (can't remember, going to look)whichever it is, why not move it one tooth? 4 to 5 or 5 to 4; and then play with the cams starting out 0,0?? this way i'll have some solid findings as to which tooth to set it to for either high-end or low-end. would be good for future reference and for any others who want to install them.

4 teeth clockwise from exhaust slot *should be* the better one for low-end right?? 5 teeth clockwise *should be* the better one for high-end?

sorry if my explanations are tough to figure out - its hard putting some of this into words... i have a digital camera on the way so i should be able to post some pics of various stuff(including where my cam gears are set @ TDC ) also i'm going to see if i can find a way to post the charts. they're all on a CD that the dyno place gave me.

personally i'm happy with what the dyno shows - the torque gains are impressive. now let's see about that high-end....

[Gen1GT]

You should have retarded the exhaust cam too. 15lb/ft at 3000, is a 8.6hp gain. 15lb/ft at 6000 is a 17hp gain. You need to move the powerband up. Nice gains though....

[naprotejay]

guys the only option i have when using the dynojet software is to *print* the charts... now, when i do that i can 'Print to file'. its a PRN file. so far i've had no success trying to open a PRN file to convert it to something compatible with the forum..... any ideas?

[charles]

You have to print it out using the command prompt.. I don't really remember the exact syntax, and I wouldn't know how to do it with a USB printer... maybe.

savedfile > LPT1 (for parallel port)
savedfile > USB001 (for USB??)

Something like that...

[naprotejay]

thanks charles.... actually i'm having no trouble printing it out; i just can't figure out a way to convert it to something that i can attach to the thread.... if i had a scanner then i could easily post them. hmmmm

[Gen1GT]

Oh, by the way Jay, one tooth is like 15.7 crank degrees...pretty big difference...especially when they recommend you only adjust the cam gear 1 cam degree(two crank) at a time....

[Marc93lx]

thanks charles.... actually i'm having no trouble printing it out; i just can't figure out a way to convert it to something that i can attach to the thread.... if i had a scanner then i could easily post them. hmmmm

take a screen shot maybee?

[charles]

I don't think he can.. needs something to view .prn files.

[naprotejay]

took a while but it worked! made a screen shot, converted it to bitmap which was 1.3MB (way too large) - finally figured out how to convert to jpeg...

anyway this is a comparison of the previous #30 INT -4, EXH 0 (116.0whp/108.5ftlbs) vs recent #46 INT -3, EXH 0 (121.1whp/109.9ftlbs)