raise the rev limiter (yo maggie!)

[Deuce Bigs]

ok this is all theoretical right now. but my plan(well this week at least)is to get the supersix heads, titanium springs, oversized exhaust valve, chromemoly pushrods, 1.73full rollers, and a comp cam. i'm thinking and hoping all that will let me take her to 6500rpms and not go boom. what do you smart people out there think. i guess this is all provided the HPP3 comes out. i just ordered the MAFT+ and i'll stick in some 3.73's in the a$$.

BTW i dunno if this qualifies as advanced or not.

[Magnus]

lol..

If its a more indepth discussion and not basic question and answer, then I allow it to stay in Advanced Tech. [img]smile.gif[/img]

Few things...

Stick with the stock valves, oversized valves are not worth the cost and I don't think they would give you HP especially on an NA engine.

1.73 rockers from Supersix are not out yet and they may not be out. Tom ran into some issues with them that he is trying to work out. I do not know how far he will get though. I don't think its his top priority right now.

You can get roller rockers from 2 companies that post over at clubgp.com.. Intense and another company. They cost around $500 or so though. :(

I'm not sure how high you would be able to rev though. You would be a pioneer and a guinee pig at the same time. Thrasher might have info about the springs and how they perform at upper RPM's. If I remember correctly Tony@Tolin told me they were good past 6300 or so.

If the HPP3 does raise your rev limiter you could do this. I don't see any other way around it though.

The only good thing I see the HPP3 for right now would be to adjust shift points. You can change timing and fine tune Air/Fuel ratios with the MAFT+.

When raising the rev limiter you have to worry a little more about parts breaking and valve float.

I suggest keeping the 6000 rpm rev limiter for saftey reasons and buying a cam with a lower power band. If you did this, you wouldn't have the need for a lighter roller rocker.

Lets say you go from the stock 1.6:1 rockers to a 1.6:1 roller rocker. I see rwhp gain at maybe 3. I have heard that LT1's will pick up 5 by going to a roller. But maybe your thinking, you would go to a higher ratio to get more valve lift... well you could save yourself $500 and get that valve lift ground into the cam. [img]smile.gif[/img]

The higher your power band is, the higher you will have to launch your car at the track to make up for the loss of low end.

3.73's... those should be nice. [img]smile.gif[/img] I can't WAIT to get mine in!!!!

- Keith

[Deuce Bigs]

well the 3.73's are to compensate for the higher power band. i was thinking of getting something in the 2500-6500 range. tony@tolin? lucy you got some 'splainin' to do.

rockers - i would get INTENSE if tom doesn't come out with them. Zooomer's are just jury rigged stock ones. BADSSEi seems like a smart cookie too.

oversized valves - just thinking ahead to possible days of forced induction.

the HPP3 would basically be for fan temps and rev limiter.

i guess if i did the cam first i could do rockers later if it really warranted it. BAD does make some 1.6:1 double rollers

i guess it would take some dyno runs to see if there is power to be made after 5K. since i still have yet to make a clean dyno run i can't tell if my torque is falling significantly past 4500. the first dyno after CIA headers my torque showed no sign of falling after 4500. my second dyno doesn't really count since i had no timing. grrr...need to get this POS runnin right before anything. you know the TB gasket part number by chance. pretty sure FUDGIN' K&N oil got all over it since i cleaned it the day before the dyno.

[navyblue2000]

i know this is more of a question, but to add to the discussion:
stock, non forged internals. what are they good till, rpm wise?

[Magnus]

Stock internals.. no clue what they are good till. I do believe our rotating assembly is rather heavy (thats why its so strong) so I don't think our cars would be much good at high revving engines.

2500-6500 is a HUGE range. Try for 4500-6500 maybe.

I believe Zoomer also has roller rockers coming out soon.

WIth oversized valves you increase cylinder wall scavenging.. If you want more flow, I say go more lift before you go bigger valve.

I do have the TB gasket part # at home. I will be bring it in tommorow and it will be in the tech database soon.

- Keith

[Deuce Bigs]

well i'm just starting to read a book on camshafts. i read 2500-6500 was a typical range but if i had to narrow it down i guess i would go for possibly 4K-6K. then i can set my rev limiter to 6200-6300 and be more safe.

[Jason McCallister]

FWIW: The HPP3 will allow you to adjust the rev limiter from 5500-6600 RPM's. :D

FYI: stock rev limiter is 5900 RPM's ;) :D

[bluecmaro96]

magnus are you going to send your computer to superchips to set shift points? even with the scu my car with 3.73 will sort of studder then shift it didnt do it with 3.42 i did see a .2 reduction going from 3.42 to 3.73 i cant wait to get pcm programmed from superchips

[Magnus]

I MIGHT send it to Superchips if they want to cut me a deal.

Stock 3.8 rev limiter is 6000.

[WickEdSix9838]

if you are still going to run a hydrolic roller, then 6-6500 is tops, after that all you will be doing is floating valves f-in stuff up, then the stock bottom end doesnt have much left in them after 6(my opinion)...forged interals are good up to, on these motors, probably around 8500-9000 which is more than the heads will handle, that is if everthing is forged,

[bluecmaro96]

when you say go for more lift than bigger valve do you mean get the cam lift raised rather than get oversized valves?

[Magnus]

Yes, get more camshaft lift instead of buying bigger valves.

[Jason McCallister]

<blockquote>quote:</font><hr>Originally posted by Magnus:
Stock 3.8 rev limiter is 6000.<hr></blockquote>

Hypertech engineers (when reading the original PCM) discovered the Rev limiter to be set (from factory) at 5900 RPMs. Maybe GM changed this in the newer models? Possibly 99 when they went to the electronic TB?

[Magnus]

Hmm.. I bet I can dig up some old autotap logs showing more than 5900 RPM's. I have a 97.

[Deuce Bigs]

what's really pissin me off right now is the damn govenor cause i can't figure out the damn optimum shift points