Max RPM on standard J4 lifters

27th February 2011, 14:52

As I don't fiddle with 16vs much / at all standard J4 head parts whats the max rpm they can rev to safely before things start to self destruct?

27th February 2011, 15:05

7600/7800 but is debatable.

Some people go to 8k

27th February 2011, 15:16

toads mapped 3 plugger went to 8k
my newmans followers failed at that and smashed the valve to bits

id personally go no higher than 7750

27th February 2011, 15:21

7.5k it is then should be safe enough

27th February 2011, 15:26

tbh gav if your running normal lifters then any cams youll choose arent going to be putting the power high enough to need to rev that far

27th February 2011, 15:29

Depends on the cams your getting i guess. Mine was set to 7400 by colin, he said best to be safe than sorry, especially when you are holding it up there all the time to get the power! Dave had newman springs didnt he? I remember reading the build, his first engine fooked up or something!

27th February 2011, 15:29

I know but just thinking if I needed to relative noob when it comes to 16v stuff, hopefully should work out qute fruity this setup.

Tufty aye I read on your blog he did that, I guess oe limit will suffice for now will see how it goes when mapping happens

27th February 2011, 15:29

i revd mine to 7850 on standards fine m8.

27th February 2011, 15:32

Quote:

Originally Posted by Tufty

Depends on the cams your getting i guess. Mine was set to 7400 by colin, he said best to be safe than sorry, especially when you are holding it up there all the time to get the power! Dave had newman springs didnt he? I remember reading the build, his first engine fooked up or something!

i think so
i really should be checking these things lol

first one was the cutouts in the pistons werent big enough for his oversized valves so they caught and one failed

new ones sweet though

EDIT: yes it did

Fully re-built TU5JP4 lump
Low friction big ends
Re-bored to 80mm
80mm Wossner Hi-Comp pistons (running 12.3:1 cr)
Forged conrods and ARP rod bolts
Modified head to accept bigger valves
Newman uprated valve springs
Newman 280 degree PH4 camshafts
AT Power iTBs with 90mm trumpets
Emerald management - 185bhp @ 7650rpm - 140lb/ft @ 6600rpm
306 GTi6 injectors
Helix Lightweight aluminum flywheel - 2.9kgs
Lightweight aluminum crank pulley

27th February 2011, 15:47

is good to have that extra available, seen a few cammed VTS and standard that power is still climbing at the rev limit

27th February 2011, 16:04

Quote:

Originally Posted by Gareth_R

is good to have that extra available, seen a few cammed VTS and standard that power is still climbing at the rev limit

really??

my old cammed vts peaked at 6800
my mate dans at 6600

even a lot of cars on itbs ect peak under 7k

if power is still climbing at 7250 then theres a lot mor going on than a set of cams

27th February 2011, 16:04

Yer wouldn't go any higher than 7.8 k

I know colin on standard followers and used to rev the engine to 8k dnt know if he pegged it though.

I have a problem as my power dose peak til 7.6k and could do with a higher limit as it still wanting to go higher but I have a soft cut at 7.6k then hard cut at 7.8k.

I dnt understand why mine is like it as I am only using oh3 cams.

But NMS moved the cams alot to get better torque and bring the peak power down the rev range. But what ever they did all the curves never changed.

But yer max would be 7.8k but that max would wanted it more peg at 7.5k if possible.

27th February 2011, 16:54

The thing with mine is, i didnt have the cams played with (timings) and mine was set up for a smoothe torque curve, toads engine made 185bhp with 140 torque and mine 139 with 170bhp

Really does depend on timings and whether you want to lose a bit lower down.

27th February 2011, 16:57

May be a tad more involved like different headwork ect fella ive seen near 170 off ph3s like jp 141 at wheels

27th February 2011, 17:10

generally we say no more than 7400rpm for continuous use.

the occasional burst you can go more, for sure. but if your down the back straight at snetterton holding it at 8k.. expect problems.

ive seen very few 16v TU engines that actually make power past 7500, unless they have had some very extensive headwork and monster cams.

- colin.

27th February 2011, 17:15

Different dyno different figures, I been too TDF and got 140 atw and it was 136 atw at NMS, but only had 500 miles on the engine when mapped at NMS, and had just over 2 and bit k on the engine and had got more bhp but the torque was the same as NMS and curves all the same.

Unsure what Jp car got at NMS was think them figures are when it was mapped at gmc, and yer my torque is very smooth and flat too. It only drop about 5 or so lbft from peaking to the red line.

So I am getting a good spread across the rev range but alittle low for what I wanted.

Any way, yer I would say 7.6k but people will let you different.

27th February 2011, 17:31

Quote:

Originally Posted by AndySAXO

Different dyno different figures, I been too TDF and got 140 atw and it was 136 atw at NMS, but only had 500 miles on the engine when mapped at NMS, and had just over 2 and bit k on the engine and had got more bhp but the torque was the same as NMS and curves all the same.

Unsure what Jp car got at NMS was think them figures are when it was mapped at gmc, and yer my torque is very smooth and flat too. It only drop about 5 or so lbft from peaking to the red line.

So I am getting a good spread across the rev range but alittle low for what I wanted.

Any way, yer I would say 7.6k but people will let you different.

only thing i remember about nms and jps car ws on there old rollers and he was pretty unhappy

and usually engines free up a bit when run in and gain a little over time especially if well looked after

ive seen a standard vts (sayers) pull as much on an rr than a breathing modified gti (my diablo) and he had a little more torque

there are so many variables in there tbh its the specific engines and thats all itll ever be no 2 are the same

anyway as said before and to stay on topic 7750

lol

27th February 2011, 17:40

O right why was he unhappy?

Yer there new rollers are good, was told they read abit lower than the last ones they had.

Think coiln been on Both and read less the second time on the new ones, but could be alot of factors involed.

NMS and TDF use the same make rollers but NMS is single roller and TDF is a double type one.

Not saying they are the best, but they both seem to read close to each other as there was 6 bhp in both and torque where both the same bar 0.3 lbft

So not far off the same.

27th February 2011, 17:56

well my 708's made 128hp at 6,500 droped to 125hp at 7,000. fly figures!!! but we all know the rollers i used was a load of crap.

i have a limit of 7,600 for safety. i abuse the arse out of mine

27th February 2011, 19:09

Quote:

Originally Posted by AndySAXO

O right why was he unhappy?

Yer there new rollers are good, was told they read abit lower than the last ones they had.

Think coiln been on Both and read less the second time on the new ones, but could be alot of factors involed.

NMS and TDF use the same make rollers but NMS is single roller and TDF is a double type one.

Not saying they are the best, but they both seem to read close to each other as there was 6 bhp in both and torque where both the same bar 0.3 lbft

So not far off the same.

im not sure tbh just not happy with the figures from that day
it was 2 years ago now i cant remember tbh

ill be on nms rollers soon and troy will be setting my limiter around where im saying as i dont trust revving engines when you dont need too

27th February 2011, 20:27

My old J4 rev limited at 8350rpm on hydraulic lifters (hillclimb use) without issues.

27th February 2011, 20:27

My hill climb VTS revs 8300k. According to the graph on the RR, the curve is peak at 8100 so i gues its useless to rev it all the way! So my shift light comes in at 7800 so that i change gear by the time it s at 8100.

27th February 2011, 20:30

I have kent cams with solid followers, stage 3 ported and gas flowed head and tb's with 60mm trumpets (Jenvey). High comp pistons, Omex stand alone, etc..
Always reved it that much! Engine is fine! I use it both on the road and in hill climbs.

27th February 2011, 20:34

Thanks for that but we are talking about the standard followers, not solid ones.

27th February 2011, 21:48

correct me if im wrong but solid followers can take 8000k up whilst hydraulic ones can take up to 8000k max! Is that right?

27th February 2011, 21:56

Well alot of people say at 8k with standard followers they will start failing yes, people state a safe limit at around 7.6kish.

3rd March 2011, 14:36

My spec was stock bottom end with valve cuts on the pistons, newman ph4 cams, stock ecu remapped. The car made 148hp at 7800 rpm and my limiter was set to 8300 with everything standart in the head. For more than 10000km i have no problems. Anyway my limiter is back to 7500 now, because it's turbo...