5 GT Turbo EFI - GT Turbo

[Mark Davis]

Here's the culprit, Chris straightened this out to get me home, drove tame and off boost pretty much all the way, the last mile I gave it a bit of boost and it obviously bent again, @Clarkey - I'm assuming once they've bent they lose all their strength/integrity and are rendered useless ? It sounds stupid but a swap for fresh one is needed before giving it any boost ?

 

[Clarkey]

I've never tried straightening mine as they are more s shaped!!!!
I personally think they lose their strength once bent but others disagree.
A new one in there should be fine. Have a look at the pushrod hole in the head for any rubbing marks.

 

[Mark Davis]

My concern is the same one bent literally straight away with a bit of boost in 2nd, perhaps 20psi tops by the time I let off. Just hoping something else isn't up, then again logically if metal has bent/deformed it would lose its strength.

Will check pushrod hole too.

 

[Mark Davis]

Whacked a new (used) push rod in there today, started and sounded sweet. Took it round the block a few times but haven't been able to test under any load/boost as it's so wet. Couldn't see any marks on head, nothing obvious anyway.

Where would I expect to see marks ?

 

[davemaygtt]

Sorry to see it didn't quite make what you wanted mark, you have done a great job as has the rest of the club giving advice. Great thread.
Silly question but what happens when you bend a rod, do you just loose some power and have some nasty noises?

 

[Mark Davis]

Sorry to see it didn't quite make what you wanted mark, you have done a great job as has the rest of the club giving advice. Great thread.
Silly question but what happens when you bend a rod, do you just loose some power and have some nasty noises?

Thanks Dave, I will keep going mate, next year I'll start looking at cam and turbo combo.
Yeah it just sounds horrible when it bends, i didn't notice it myself but Chris knew straight away on rollers. When I was nearly home and it bent again it just sounded rough and was missing.

 

[Clarkey]

Couldn't see any marks on head, nothing obvious anyway.

Where would I expect to see marks ?

If you look a the hole where the pushrod goes through the head, look for any signs of rubbing/wear.
Yours should be quite easy to spot with the new head as probably got some paint on when CTM made it all look pretty.

My pushrods are probably only one or two mm away from the head.

 

[Mark Davis]

If you look a the hole where the pushrod goes through the head, look for any signs of rubbing/wear.
Yours should be quite easy to spot with the new head as probably got some paint on when CTM made it all look pretty.

My pushrods are probably only one or two mm away from the head.

I think there are two very faint marks that have gently chipped the paint/finish which would make sense where the shape of the rod has changed.

Surely that's purely cosmetic @Clarkey ? Nothing to be concerned about or ?

 

[Clarkey]

I think there are two very faint marks that have gently chipped the paint/finish which would make sense where the shape of the rod has changed.

Surely that's purely cosmetic @Clarkey ? Nothing to be concerned about or ?

I mentioned the paint finish as will make it easier to see any rubbing, certainly not problem.

When you have bent as many as me, you should start worrying, you will be fine.
I have issues on my set up and bent pushrods from day one.

 

[Mark Davis]

Yeah I will keep an eye on it. Mine was fine on the rollers at both 23/25psi but then on run 3 at 27psi it bent. Obviously just concerned this is going to keep happening but as the weather has been so poor i've not been able to go out for a good run.

Theoretically, is there any other damage a bent push rod could do? Do you tend to pull over instantly @Clarkey or do you race on?

 

[Clarkey]

No other damage, just runs on three cylinders. I would nurse it though if it was my road car.
Because race car I have raced on, to finish the race. At cadwell had a good battle with a civic for a couple of laps he was gutted when I told him, it was only running on 3.........

Was so desperate to finish the race at Silverstone this year, we actually snapped the rod!!!!

 

[Mark Davis]

Haha, that's the spirit mate, destroy those Civic's in any way possible.
Will report back once i've had a good run with some high rpm/full boost shenangians.

 

[Mark Davis]

Yeah count me in with the push rod thing, more than happy to put some cash in.

Been out today for a good hour, it was a bit damp but dry enough to test. It didn't start well as for some reason vac hose worked its way loose from the FPR and started juddering all over the place, I could hear vac leak in car so luckily let off straight away. Pulled over and sorted it with a good old fashioned cable tie.

The very next run car was missing again which I couldn't quite understand, soon realised the car was overboosting to 30psi and hitting boost cut. Tweaked wastegate duty back down to 26psi and all was fine.

Very impressed with the car, pulls hard through all gears and is feeling rapid, hopefully we will get a couple more dry days this week to play further.

Only down side seems to be the gearbox has developed a bit more of a constant whine so may have to look at a diff sooner rather than later.

 

[andybond]

A diff will transform the car.

 

[andybond]

If you are looking for bending pushrods I moved it here !

5 GT Turbo - c1j pushrods thread.

 

[Mark Davis]

A diff will transform the car.

Really didn't want to have to fork out a large sum until next year but it box goes I might as well upgrade to LSD. Just need to decide which, it will mostly be road use with the odd track day/sprint.

 

[DaveL485]

Tweaked wastegate duty back down

Check you out mr expert

Funny how it seems to creep up compared to the dyno settings isnt it, mine did exactly the same too.

 

[Mark Davis]

Check you out mr expert

Funny how it seems to creep up compared to the dyno settings isnt it, mine did exactly the same too.

Only Mr expert on the wastegate tab as you told me a few weeks ago.

Really need to explore what else the ecu can do, would also like to get launch control sorted.

Yep 3/4psi difference from rollers to road. Quite liked seeing my gauge fly round to 30 though.

 

[Mark Davis]

RENAULT 5 GT TURBO NEW FULLY ADJUSTABLE SUSPENSION TOP MOUNTS (PAIR) CMB4455 | eBay

@Clarkey - do you run these or something similar ? I'm still not convinced by my handling, not enough caster, it barely self centres.

I'm guessing some modifications are need to struts to fit these ? Any advice would be appreciated.

 

[Clarkey]

Yes that

RENAULT 5 GT TURBO NEW FULLY ADJUSTABLE SUSPENSION TOP MOUNTS (PAIR) CMB4455 | eBay

@Clarkey - do you run these or something similar ? I'm still not convinced by my handling, not enough caster, it barely self centres.

I'm guessing some modifications are need to struts to fit these ? Any advice would be appreciated.

Yeah that what we run now Mark. We had our dampers altered by Gaz for correct fit as we run Gaz monotube and the top thread is slightly different.

We had 2.5 degrees castor with these top mounts, we wanted more so cut them about to give us 4.5 degrees, which is better, was hoping to get over 5 degrees.

Lots of castor will cause you pretty heavy steering on a road car, not a problem for a track car.