Need 20hp more..

[Kokkolanpoika]

Hello all.
New here..

I have got Rover SD1 "vitesse replica".
It has got 5.2litre RV8 engine. It has dynotuned 340RWHP and flywheel 381hp@5560rpm and 543Nm/3910rpm (over 500Nm between 2700-5100rpm)

Specs. 96mm bore and 90mm stroke with forged crank.
Compression ratio 10.8:1 (measured)
Quench clearance 1mm
Realsteel RS M238 mechanical cam.
Roller rocker from Harland Sharp.
Home modded heads with 43/38mm valves and 7.93mm stem. Single valve spring.
Consumption champer ported to suit bore.
Home made 4-1 exchaust maniflod, primary tubes 41.5mm and lenght 750mm.
Collector 2.5" and home made 2x 2.45" SS 316L tail pipe inc X-pipe and 4x mufflers.
Engine magnament Haltech F10 + MSD 6AL + MSD dizzy.(coming megasquirt 3 next winter inc 8x race coil).
Jenvey 48mm throttle bodies inc 40mm lenght air horn. JE manifold.
JE steel 8kg flywheel inc BMW e34 M5 Sasch race pressure plate and Ford mustang organic clutch plate. Holding +600Nm at least.
Tremec T5.

I want to break or get close 400hp limit with those heads.

Is it possible?

My next plan is to Fit MS3X ecu + 8x race coil to run at least semi sequential mode.
New Cometic head gasket to reduce quench to 0,8-0.9mm. And slightly milling heads to get 11.5Cr. Fit Crane cams douple valve spring to allow engine rev more than 6300rpm.
Fit Realsteel M248 camshaft.?
+ try to change air horn lenght?
+ extra maybe flow bench test head´s and look at what they say? Many of my friends are intresting my head results..

Any ideas is it possible to get 400hp with home made rover engine? Any ideas?

Edited by Kokkolanpoika on Thursday 13th October 14:10

[davepoth]

If I were you I'd be looking at the bottom end; the 5.2 has a very long stroke and won't like revs which is what I think you'll need to do to get power on that setup, assuming the flow is OK. Definitely get the heads on a flowbench.

[Pumaracing]

Looking back through some of my old flow bench tests 170CFM @ 25" pressure drop is a decent target for the 3.5 litre heads with 43mm valves. I don't know if the heads on the bigger engines differ. Putting those flow figures into my power prediction software you are already doing rather better than I would have thought possible which makes me wonder about your dyno accuracy. TVR struggled to break 300 bhp with their 5 litre Griffith engine and the quoted power claims were somewhat massaged according to the guy who actually built the engine for the magazine road test car when I spoke to him many years ago. It wasn't even a 5 litre engine in reality but that's another story. To try and even get close to the claimed bhp figures they stuck a long stroke crank in it - allegedly of course.

You'll never even notice another 20 bhp anyway so why bother? Don't even think about reducing quench clearance below 1mm. It'll make f**k all difference to power but it'll make a significant difference to engine reliability if crank flex and rod stretch mean the pistons hit the heads. That's generally considered a bad thing n'kay. A 248 cam will be a pain in the cahonas to drive on the road and I suspect you'll come to regret it if you fit one.

You are probably already somewhere close to the peak of the sweet spot between gaining a tiny bit more high rpm power and losing a st load of low rpm and mid range tractability.

Leave it alone and p1ss your money away on something more important like booze, wes and large screen tvs.

If you're determined to mess with it then bigger inlet valves and porting to suit is the only way to go. The exhaust valves are already plenty big enough so leave those alone. Read the tuning articles on my website. If you can't find my website then your Google skills need work.

Edited by Pumaracing on Thursday 13th October 19:42

[Pumaracing]

The hell? This forum filters out S H 1 T when I've already replaced the i with a 1 and I can't even type W H O R E S? Who do they think reads this stuff? 15 year old evangelical christian girls with fragile sensibilities? Bah humbug.

[Kokkolanpoika]

Thanks for replay..

Tuning Rover V8 in Finland is quite rareness, and i like to look at my ability, that´s why i want to get near 400hp.. And also show my skill´s to tune Rover engines without any training/experience to car´s. Maybe i´m crazy or some lunatic then? Rover car´s is family fault..

My engine´s drivebility is like stock car, thanks to Jenvey throttle bodies. With siamesed plenum it is slightly difficult to drive, but ok to traffick. So i assume that with M248 camshaft + ITB´s drivebility is similar like siamesed plenum..
Back to Quench: My current composite gasket is 1.2mm thickness and new Cometic gasket is 1mm thickness. And my current quench is approx 1-1.1mm max, cant remember. So with new gasket it is approx 0.8-0.9mm. Is it better to slightly modify consumption champer to raise quench? I think 0.9m is still safe side. My friend runs´s approx 0.7mm quench without proplem (Opel CIH and Ford OHC)
Problem to use current +1.2mm/97mm bore head gasket is their quality. They look like crap to my eye vs elring. They leak oil + etc.


Dyno graph:



Uploaded with ImageShack.us

My car + engine building: Finnish rover forum:
http://www.roverfriends.fi/foorumi/viewtopic.php?t...

So is another way to go over 400hp to buy new heads Ta-performance or wild cat?

[stevieturbo]

Did Real Steel ever get their "Merlin" head castings finished ?

More power...add boost lol

[Zad]

Might dry sumping it help? Not cheap if done right, but at least it shouldn't make it harder to drive, unlike a peaky cam etc.

I don't know much about Rover V8s, but I would have thought the inlet trumpets and plenum would be optimised for a particular rev range and/or air flow.

[stevieturbo]

Fit an LS1 ? lol

[Kokkolanpoika]

LS1 is illegal engine. Thanks to Finnish law. Stock (biggest/powerful) engine 3528cc + 25% more cubic inches and +20% more power. So approx 4410cc and + vitesse 193hp + 20% = 231.6hp. That is legal..
So have to stay with Rover.
Boost is one choice also? But i like more naturally aspirated engine..

[Pumaracing]

I'm not sure why you are so concerned with reducing quench clearance because once you get to about 1mm it makes little further difference to power going even lower than that and can in fact make an engine more prone to detonation rather than less. I've experimented with quench as low as 0.6mm on one engine at which point there was evidence that the pistons were only just missing the head at high rpm but it showed no advantage over a wider clearance. Nowadays I stick to 1mm as being both safe and also obtaining the vast majority of any potential benefits to be had. On a low revving engine like yours I'd be happy enough at 0.8mm if there was some particular need to have to do that.

[stevieturbo]

Fit an LS1 and stick big "Rover" stickers on the rocker covers ?

Or Fab up some nice Rover looking Rocker covers for it.

[ian_uk1975]

Impressive numbers (and a good curve) for an NA RV8!

More head and more RPM for more power, but I'd leave it alone or go FI (but that will require tearing it apart and starting from square 1 again to do it properly).

People seem to get hung-up on quench for street applications... my quench is somewhere around 0.058" (383 sbc), but I'm not trying to wring the very last ounce of power from the motor as I'll never notice it on the street. Safety first What I AM focusing on is a much better exhaust, as that thing is costing me >100bhp right now!!!!

[chuntington101]

stevieturbo said:

Fit an LS1 and stick big "Rover" stickers on the rocker covers ?

Or Fab up some nice Rover looking Rocker covers for it.

Now thats a grat idea! you could also run a carb style intake to get the authentic look.

[Kokkolanpoika]

We made about month ago flow bench testing with my home made rover stage4 heads vs my friend merlin. Without any porting etc. Measured @ 28"

Figures: 1.7" inlet and 1.5" exchaust
Exchaust measured without tube/flange.We add only tube with our hands, made approx +10cfm more flow.
inlet exchaust
0.1" 61 63
0.2" 119 100
0.3" 155 135
0.4" 161 153
0.5" 166 141
0.6" 170 137
0.7" 171 136
Gas speed is optimal 250??? unit, dont know what?

STD merlins flow 6cfm more with inlet and approx 20cfm less with exhaust..

I just found that my single valve spring are too loose, 29Kg seat pressure and 13mm valve lift 79Kg. Realsteel DW 044?
New crane douple spring´s are seat pressure 45Kg and 13mm valve lift 110Kg. Same installation height 39mm.
+ My new static compression ratio is approx 11.77:1 and dynamix 8.66:1.
+ champer is slightly ported more near exchaust valve to give better flow.

I hope my engine will rev more than 6200rpn now and made couple of hp more than last year.
+ I´m firing MS3X in it + 8x ignition coil to give fat and desent spark..

So i still spend my money in my car, not whor.s and beer..

[Kokkolanpoika]

I forgot to say.

I dont´t believe flow bench testing´s vs real world horsepower. Those bench testing´s are some stupid numbers and parameters.. We have seen too many times poor head flow results and in rolling road/dyno those power numbers are mutch better..There is nothing to do with serious horsepower vs flow bench readings..
Head porter calculate that my inlet track lenght is 20mm too short, so it is quite optimal. Cam is too mild, need more duration, over 300deg, lift is quite ok. Yes yes, i know that.
I believe Pumaracing word´s i wanna keep my car drivebility still, so if i want to broke 400hp someday, i will order new cam or bought new head´s.. Wild cat´s etc..

Still looking 400hp someday with home made rover engine..

[rev-erend]

It sounds very impressive - nice job.

Hard to see how you can better that ..

Maybe - slightly straighter run to back of value.. yours has a bend..

Maybe increase exhaust header from 1 5/8inch to 1 3/4 inch ..

Improve the 4 into 1 collector - it looks a bit crude. I used one off the shelf from Jegs in USA
http://www.jegs.com/p/Dynatech/Dynatech-Slip-On-Co...


Maybe - second set of injectors above throttle bodies with cut in at high rpm..

All of the above also might not add anything.

NO2.

Edited by rev-erend on Friday 20th April 17:41

[Alexdaredevilz]

I run a m248 cam on my 4.6 with no issues round town running on stock 14.cux

With your set up I'd consider a m256 or a custom grind

Is there a few horses available with some more mapping fuel/ignition?

[Kokkolanpoika]

I just start to fit MS3X ecu. My old setup is Haltech f10 witch has got fuel maps only and adjustment only 500rpm step´s. + MSD dizzy.. I think drivebility is better with adjustable ignition maps and semi/full sequential will give slightly more hp?
If i but M256cam i need to run some silly compression ratio´s like 13:1 to give dynamic near 8.5-9?
Those 381hp readings are measured in dyno and fuel maps are adjusted and also ignition timing is adjusted.. So no more ponies with haltech.