N/A builds, by NitroDann

greenMachine · Postby **greenMachine** » Mon Jul 27, 2015 10:53 am

greenMachine wrote:
slug_dub wrote:
greenMachine wrote:I ran an atmo 100+rwkw car with biggish road/race cams on the stock ecu, with boosted fuel pressure (NB8A).

Whats the specs on your biggish road/race cams greenMachine?

They were a Tighe item. Probably mentioned on here but I can't remember the number.

Closest I could come: viewtopic.php?f=44&t=35422&hilit=+tighe

:mrgreen:

93_Clubman · Postby **93_Clubman** » Mon Jul 27, 2015 1:48 pm

greenMachine wrote:They were a Tighe item. Probably mentioned on here but I can't remember the number.

May be 898c?
In 2007 Tighe were supplying the 898c custom billet based on their existing 805c, but reworked for the NB solid lifters.
Specs were:
Lobe II
Centerline 111.0 BTDC
.050 lift C/L 112.09BTDC
Runout 0.00000
Lift @ TDC 0.0469
Valve Lash 0.0000
Rocker ratio 3.00
Lobe seperation 113.0
Minium flat
Follower dia. 1.1211

Lobe EI
Centerlne 1.5.00 ATDC
.050 Lift C/I 1.3.44 ATDC
Runout 0.00080
Lift @ TDC 0.0406
Valve Lash 0.0000
Rocker ratio 1.00
Lobe sepertaion 113.0
Minimun flat
Follower Dia. 1.1234

hks_kansei · Postby **hks_kansei** » Mon Jul 27, 2015 2:01 pm

Going to assume those lift measurements are Thousandths?

so 11.9 and 10.3 mm in metric?

madjak · Postby **madjak** » Mon Jul 27, 2015 2:11 pm

rascal wrote:As does removing some overlap. I've got biggish cams in my NB, and lots of overlap and it sounds like a rotary at idle (had more than a few people think it was)
Recent events saw me change the cam gears, and I've ended up with much less overlap than before and the idle is much more normal like..

My engine picks up lots of power due to the cams so if I was building a fast N/A street car and wasn't too worried about a lumpy idle I'd go as wild as possible. FWIW my cams are around 260 duration @ 0.05" and over 320 @ 0.01". That gives me around 55 degrees of overlap which is crazy. It would be massive overkill for a street car but it's way way more than the tighe cams.

I've posted this in my garage chat but here it is again:

What about the Maruha cams? They do one that is 288 degree and suitable for SUBs.

93_Clubman · Postby **93_Clubman** » Mon Jul 27, 2015 3:49 pm

hks_kansei wrote:Going to assume those lift measurements are Thousandths?
so 11.9 and 10.3 mm in metric?

Yep, Imperial - haven't got the specs in metric, but your conversion is accurate.

madjak · Postby **madjak** » Mon Jul 27, 2015 5:18 pm

What you have posted is the valve lift at TDC.... 0.04" which is around 1mm as the valve is only just starting to open. Total valve lift is a different value and will be at around 100 ATDC and not listed in your specs.

hks_kansei · Postby **hks_kansei** » Mon Jul 27, 2015 5:58 pm

madjak wrote:What you have posted is the valve lift at TDC.... 0.04" which is around 1mm as the valve is only just starting to open. Total valve lift is a different value and will be at around 100 ATDC and not listed in your specs.

Ahh, so it's 0.04 inches. (not 400thou)

I thought it may have been, but when I converted to metric it was only about 1mm, which seemed way too little (I was assuming it was total lift)

93_Clubman · Postby **93_Clubman** » Mon Jul 27, 2015 6:01 pm

Specs weren't put together by me, so just including what was provided back in 2007.

hks_kansei · Postby **hks_kansei** » Mon Jul 27, 2015 6:16 pm

93_Clubman wrote:Specs weren't put together by me, so just including what was provided back in 2007.

I think the issue is more that I read them wrong.

madjak · Postby **madjak** » Mon Jul 27, 2015 7:07 pm

Given the specs you have posted, my guess is they would be around the 215 degree duration mark, given a centerline of around 111. They look pretty close to the turbo cams from Kelford specifically the Kelford 235-TA.

CAM NAME No | LIFT | DUR | CEN | LIFT @ TDC
Kelford 235-A | 8.95 | 220 | 108 | 1.47
Kelford 235-B | 10.0 | 230 | 106 | 2.28
Kelford 235-C | 10.2 | 238 | 104 | 3.00 (full race cam)
Kelford 235TA| 9.00 | 216 | 110 | 1.11
Kelford 235TB| 10.0 | 230 | 108 | 1.81

pcmx5 · Postby **pcmx5** » Mon Jul 27, 2015 9:52 pm

805C's are 252 duration.

Peter.

madjak · Postby **madjak** » Mon Jul 27, 2015 10:10 pm

That will be the advertised duration not the duration @ 0.05". That Kelford turbo cam has an advertised duration of 256 which is very similar.

madjak · Postby **madjak** » Mon Jul 27, 2015 10:21 pm

Just to clarify... It's best to quote the 0.05" or 1mm duration instead of the advertised duration. The advertised duration contains the lead-in/out ramps which can be misleading on how lumpy a cam is if it has a soft ramp.

All the figures I posted above are the 0.05" lift duration.

pcmx5 · Postby **pcmx5** » Mon Jul 27, 2015 11:09 pm

ok so 805's are 222 and 725C's are 232.

Peter.

93_Clubman · Postby **93_Clubman** » Tue Jul 28, 2015 12:58 pm

madjak wrote:They look pretty close to the turbo cams from Kelford specifically the Kelford 235-TA.

Did look at the Tighe Cams website sometime ago, but apart from for the Subaru WRX, there's no reference to 898C. The cams were supplied by Tighe, & based on their 805C, but custom made for a naturally aspirated NB8A, however will also suit an NA8 with solid lifters.