8000+ rpm on 20vt

Hi, searching for real life experience what is needed to mod of stock engine to like high rpm.

We have two race 2ltr engine builds with bigvalve head and overkilled by 280-290deg cams on solid lifters. Lightweight pulleys, chromemoly flywheel.
Stock oil pump, water pump and valve springs(but fresh new).

First engine tuned,and peak power on modest constant boost 1.6bar (GTX3071 gen2) is just after 8500rpm.

I dont know if it safe to let engine runs in race mode over 8000rpm. First test after dynotuning showing bit of water temp issues (car have bigger alloy radiator + evans coolant).

thanks

The best person I can suggest to ask this question to is Leighton from FC Performance, he's mapped 20vt's up at this rev range.

User name Flea on here or:

www.fcperformance.co.uk

I believe JohnS ran his 2.4 converted Coupe at up to 8,000 rpm, but he found that anything above this caused valve-float (even on new springs)

I would have thought that uprated springs and possibly solid lifters might be needed for a race engine where it's going to spend a lot of its time at high revs

I did run mine to 8000rpm, but doubt it did much to help with engine life. Replacement engine was built with solid lifters, engine builder assured me that hydraulic tappets would not be reliable if using 8000rpm regularly - might be OK on road, but not for a race engine

Thanks,

just tried to send email to Flea, but i think he has better thing to do than waste time on answer.

Is there any uprated springs available for 20vt or it must be customized by searching from performance manufacturers catalogs?
We are on solid lifters(already have problems with failed hydraulic lifters = cracked retainers).

Audi 5cyl have problems with oil pump gear, which regulary blowns at 8000+ rpm.

Water pump, we are on decision go for electric, for now still with oem in place(due timing bell gear).

That sounds like very high rpms for peak power on that turbo... What is peak power?

I agree - I have the same turbo and my power is dropping off after 7,000rpm. I'm guessing that he's running the larger 0.86AR turbine housing, which will shift the power band upwards by 500+ rpm

I'd hope the power figure is going to be in the region of 500bhp, otherwise there's not much point chasing the higher revs

Power is 500bhp+ at 8300rpm(dyno read,ecu saw 8500 - limiter), at 6500rpm it has only 400bhp and at 3000rpm only 75bhp. V-band .61 housing + 45mm wg. Its overkilled by cams as i noted.

Engine builder says oil pump is ok as its gear driven by design. So he see first problems on valve train now.

Been a while since we have had a thread like this. Please keep us posted with progress. It's an interesting read

springs for 20Vt doesn´t exist - directly intended (if Catcams doesn´t make one) but as the 5cyl engine is same- base design as twinspark there is a chance to use twin spark springs which are available from AHM, Catcams etc..

http://www.ahmotorsports.co.uk/product/twin-spark-cup-race-springs/

this recommended by catcams for TS witch hig-lift/race cams:
http://catcams.co.uk/acatalog/1031575.pdf
http://catcams.co.uk/acatalog/PAC-E92009.pdf
http://catcams.co.uk/acatalog/PAC-I92009.pdf

There is something unusual about your engine - mine briefly made 500bhp, but was backed off for safety. My redline is set at 7,300rpm

I think it would be cheaper for you to sort the cams than to try to get the engine to survive 8,000+ rpm

Try Colombo & Bariani for cams

regarding to cooling issues - if they occurs at high rpm - there is probably problem with cavitation on water pump blades which stops water from flowing..

the radial impelers in pumps has best eficiency around 4000 rpm, above that speed, severe cavitation occurs and little bit higher the flow is interupted so at least lowering pump speed by increasing pulley diameter is the way (on this engine hardly to made..)

.. electric pump and deleting impeler in std. pump is probably the way...

Here is a dyno chart. Absolute values are say estimation, due several dyno limitations(3rd gear pull,inertia loaded). But for curve shape is enought.




Now i have there a different coupe with the second engine(almost same build) where owner is more hero rated, equipped by GTX3582r gen2 and same cams timmed little more to higher rpm,unfortuantely(due more limited valve/piston clearance).

Honza: thanks for springs, will check it.

What about Rods / Rod bolts- thought the rod bolts started to give around the 8,000 rpm mark also?

Bigends ran his at 8200RPM and didn't have any valve float from what flea said when i asked him.

As for uprated valve springs etc there are some on the market and they are available through a certain supplier and cost is around the £550 mark.

As for CAM's i wouldn't bother going C&B unless

(https://www.gazzellaracing.com/product.php?productid=17909&cat=2779&page=1)

you want to pay over the moon (£1300) and wait a lot longer than the 40 days they say it will take (thats what happened to me) The same supplier have there own cams made from blanks (no cheap re ground bodge) and come matched the same as C&B specs plus 2 other specs for different use. Prices start at £800

Hope this helps little

Hi all! Yes on mine (long time ago in a far away galaxy) I think there was some detection of bounce at over 8000rpm therefore the rev limiter was pared back to 8000rpm. There is a possible risk of hydraulic lock out of the lifter, at the time it was a failing on some of the VAG turbo engines with similar lifters. I remember someone posted a modification to the lifter to stop this happening years ago.
Using higher revs it's even more important that the engine is dynamically balanced and all the pistons and rods are exactly the same weight etc.

If your power is still rising at 8000rpm then something is wrong-sized in the inlet or exhaust in principle. Whatever the cams you have there is some adjustment on the cams as standard, so you can actually change the characteristics of the engine a little bit just by the adjustment available.

I tried a GT3582R twin-scroll setup on mine but it didn't suit the engine at all, so I ended up with a custom GT3082R with 0.7AR T04 cold side and 0.86 hot side.

Thanks for a reactions. JohnS run hydrolifters , so ok we have that solved.
Blancing is a sort of issue due 5cyl, it can be done by some counterweight, but there is a place for a mistake, so we do not touch crank, and balanced are only other rotating parts mounted on it. Pistons and rods are paired to make weight, but not laboratory perfect i think.

Here is a dynochart with second engine GTX3582r g2 equipped.Its different dyno than first one, but still only dynamic loaded, measured on 4gear. Vanos-VVT is activated all the way the 8000rpm, because still benefit. There is no more space piston/valve on intake side to make adjustment more to "low end" (i can note exact numbers if anybody want).
Boost was 2bar, but have creep issues over 7500rpm and run out ouf fuel flow due car is on E85.

Intake manifold is OEM only slighly ported to match bigvalve head.

Actual plan is to fix fuel and creep, run again ut to 8500rpm and try advance more exhaust cam, but not expecting much torque gain from that.

what intercooler set up are you running i find the Pro alloy one most of us use is very restrictive and the Evo design one not much better.

Its some kind of US ebay biggest china FMIC with 3" outlets dimensions. Just core is not classic bar/plate design, but tube/fin...and china just forgot made the fins so inside it looks like "tube 3" on this picture:

http://www.carparts.com.hk/Image/Intercooler/tunes.jpg

Car have maxigauges display with dataloging and temp sensors before and after IC, just it was no opportuninty to log+check it. All i know on 1/4mile drag, with 20degC ambient, MAT temp was 70degC at finish.
Have a plan to borrow same size pure china bar/plate FMIC, test on a dyno. But it doesnt have a priority,now.

How did you measure a IC restriction? Two boost gauges/map sensors?

http://www.fiatcoupeclub.org/forum/ubbthreads.php?ubb=showflat&Number=1609159#Post1609159

There is a thread mate take a look