leogurvich

Hey guys,

I have a built button end 1.6 motor running around 300whp @20lb of boost.

My exhaust valve is leaking in the third cylinder. Now it's time to pull the head off. What do you recommend I should change on the head since I am going to have to send it to machine shop.

I am not trying to go crazy a spend bunch of money, however I do want to do anything that would help me spool up better

i should mention that this is mostly track car, stripped na with 6 speed.

leogurvich

Should I just buy a remanufactured head from eBay and call it day or spend the money reworking the head out of my motor?

LeoNA

If your head is rebuildable, flat and not cracked I would work with a local machine shop to have it rebuilt. Aftermarket valves will be stronger and flow better. Manely or ST will be back cut and they might offer 1mm oversize to offset the sinking from cutting the seats. You might consider doing a little porting. Do not open up the bowl area/throat too much. Good quality springs are important.

sixshooter

iTrader: (12)

Double valve springs and titanium retainers

Watterson02

In terms of porting, a lot of people go for the short side radius of the intake (maybe the exhaust too, I'm not 100%) and then leave most of everything else untouched to maintain port velocity.

leogurvich

So my builder ended up giving me a better head for free as he was rebuilding mine. Turns out that my head was actually warped and the guys who rebuilt it last time did not even check for it ( was a different owner before me). I am shocked the car ran that will with cams that one could not even turn by hand

More that I have the motor back together and Dyno at 270 who at 20psi on e85. I am starting to think that I wasn't to replace my exhaust manifold and turbo to be able to get more boost

What do you guys recommend for a turbo that could go up to 30psi with reasonable spool time.

I know everyone is going to recommend going to 1.8 motor but I already have fully built 1.6 so I do not want to start from scratch.

sixshooter

iTrader: (12)

G25-550

Watterson02

I haven't actually compared the G25-550 and GTX Gen2 2867R side by side until just now, but it does seem that the G25-550 is going to be the best turbo for your goal. I looked at my g25-550 results vs AndyFloyds. We both have very similar builds except he has the Kraken Low Mount which should help the spool time more than my side mount set up. He hits 18psi right around 4100 rpms in 5th gear and I was able to hit it around 4000 rpms in 4th gear. I was also using open loop boost control here and not closed loop so my numbers could definitely be improved upon (I plan on retuning ignition timing for more power with the Octanium Octane booster like he recommended and I am running closed loop now so my turbo's lag should be reduced). I'm not sure if he used OL or CL boost control in his testing though.

Both of these options should get you to around 450whp or more on E85.

leogurvich

Are both of you using built 1.6 motor? Also what transmission are you running?

Watterson02

Both of us are running 1.8s with the 6-speed. I'm running 83.5mm pistons and he's running 84mm, if I'm not mistaken. I think we've not blown them up yet since neither of us track our cars. I personally think heat is a big factor as to why the 6 speeds blow up, but then again I don't really have much evidence to support that except Z_WAAAAAZ blowing up his 6 speeds on only a GT2560R at around 270wtq

leogurvich

Mine is a full race car, running with slicks and under 2k lb. I have gone through one 6speed already.

How do you think the numbers would look with 1.6 built motor?

Watterson02

I can't comment much on the 1.6 turbo lag, but if I had to guess it'd spool up about 300-400 rpms slower than a 1.8. Maybe a more experienced person can chime in here since I've only ever turbocharged my current car with the 1.8.

Personally, I think if you're genuinely planning on making anything near or over 300wtq on a track car just go ahead and look into a transmission swap. I've not had to cross that bridge yet, but plan on it within this year. In terms of power, around 30psi with a 1.6 on E85 I think you'd be in the mid 400s with the G25-550 maxed out due to its maximum rpms. That's at least what the compressor flow chart seems to say.

Watterson02

After commenting in another thread, I realized I completely forgot about the EFR turbos. The EFR 6758 is likely to outperform the G25-550 in both power and spool time. Only issue is that the EFR is going to be the most expensive option.

leogurvich

Do you think it's worth doing low mount given that is more difficult to work on the car?

Watterson02

Low mount pros:
- lower center of gravity
- better spool/power due to a straighter downpipe and exhaust runner design
- personal opinion on aesthetics

Top mount pros:
- cheaper
- very similar performace
- more accessible
- personal opinion on aesthetics
- can use factor water pump outlet

It's a personal thing all the way through. For me, the cheaper and easier to work on route made the most sense.

leogurvich

If you were to quantify the spool of top and button mount manifold, how much different do you think they would be?

sixshooter

iTrader: (12)

Fractions of a second