How close to the redline do you turn?

[bennybigb]

Hello Guys,  we are putting things together for the upcoming Gingerman Chump race and I was wondering how close to the redline we should run our 82 Celica with 22r motor?  During practice we run it up to 5k, but for a 14 hour race should we dial it back for reliability?  What should our down shift revs be at?

 

Any other tips to make this thing last 14 hours?

 

Thanks,

 

Ben

[mender]

For the most part, a mechanically sound engine can run at or near its design limits for extended time as long as it is kept at the correct operating temperature and the oil pressure is at 8.5 to 10 psi  per 1000 rpm.

 

In other words, keep it cool and supplied with good oil and don't overrev it and it shouldn't blow up.

 

Downshift revs should be as low as possible. Don't use the engine as a brake. When I watch a video I listen to the engine rpm when the throttle is picked up coming out of the corner; done properly, engine rev matching should have the engine very close to the same rpm. I do my downshifting as late as possible, just before needing to get back on the throttle and that keeps the engine abuse and extra fuel usage to a minimum.

 

The old-school redlining of the engine on every downshift sounds racy but does nothing except put the engine at unnecessary risk.

[Team Infiniti]

15 minutes ago, mender said:

a mechanically sound engine can run at or near its design limits for extended time

True and the 22r engine is a street proven workhorse, but, according to Lemons FACT, when you bring that old farm horse to the race track it is almost certain death via broken connecting rod.

 

Research this more on their forum ( 5 pages show up)

Ex:

"

I ran a 22R hybrid (22R bottom end 20R head) for about 10 races in a 2nd gen Celica and my brothers team ran a 3rd gen with the 22RE. They are capable reliable engines with reasonable torque, you just need the the right rearend gear ratio to keep the rpm at around 4300 max. The Celica's can be made to handle well and are reasonable light but they are definitely momentum cars so you have to drive the crap out of them to be competitive and a large fuel cell helps as well.

The problem is that without spending stupid money you can't get a lot of HP out of these engines (maybe 115-120 HP) and when you get the car set up and drivers at the best you will want more HP than you can get from a 20r/22r on Lemons budget. When our last engine dropped a valve I priced up building a good enough engine with ebay pistons(22r in a 20R block), RV cam, oversized valves etc and the machining costs alone were going to get me out of budget to still have a slightly underpowered engine"

 

and

 

The same could be said of the NA Supra straight 6 or the 22R, etc, etc.  They just do not break on the street or in normal racing but have them run a LeMon's event or two and they will bounce connecting rods off the pavement. "

 

Edited July 4, 2017 by Team Infiniti

[mender]

What was the cause of the connecting rod failure?

 

I've also heard that SBCs don't last ...

[Dcwilliams00]

bennybigb....engine swap. Have you ran the 22 yet?

[Team Infiniti]

46 minutes ago, mender said:

What was the cause of the connecting rod failure?

 

I've also heard that SBCs don't last ...

No dog in the fight, just reporting the known collective knowledge of those on the other side, it just seems certain engines dislike extended rpm.

 

 

[Ron_e]

1 hour ago, Team Infiniti said:

No dog in the fight, just reporting the known collective knowledge of those on the other side, it just seems certain engines dislike extended rpm.

 

 

 

For sure.  Similarly a stock Honda is bullet proof on the streets, on the track not so much.

[pintodave]

4 hours ago, mender said:

For the most part, a mechanically sound engine can run at or near its design limits for extended time as long as it is kept at the correct operating temperature and the oil pressure is at 8.5 to 10 psi  per 1000 rpm.

 

In other words, keep it cool and supplied with good oil and don't overrev it and it shouldn't blow up.

 

Downshift revs should be as low as possible. Don't use the engine as a brake. When I watch a video I listen to the engine rpm when the throttle is picked up coming out of the corner; done properly, engine rev matching should have the engine very close to the same rpm. I do my downshifting as late as possible, just before needing to get back on the throttle and that keeps the engine abuse and extra fuel usage to a minimum.

 

The old-school redlining of the engine on every downshift sounds racy but does nothing except put the engine at unnecessary risk.

 

All of this. Especially the down shifting part. 

 

In our experience, taking a stock SBC that can run 5900-6200 (depending on the factory heads/cam of course), they seem to live for a long time even using stock components when running it in the mid 5000's, so that is racing it at 10-ish% less than "running at the redline". 

 

Edited July 4, 2017 by pintodave

[mender]

1 hour ago, Team Infiniti said:

No dog in the fight, just reporting the known collective knowledge of those on the other side, it just seems certain engines dislike extended rpm.

 

 

Not trying to make a point; I'm always curious about the background and context of engine failures. My tach telltale was always at 6600 rpm for the first couple of race weekends despite the fuel cutoff of 6300 rpm. Watching videos helped me spot the rod-stretcher in our midst; yes, his upshifts were at 5500 rpm but the downshifts weren't.

 

For my V6, I have the shift light set at 5500 rpm but will run it just past 6000 if the gearing is out for a corner.

[PNWZR1]

Engine redlines at 7,500. Short shift at 6, unless needing to power to get around another vehicle.

[Ogren-Engineering]

9000 everytime

[pintodave]

Oh, there was that one time that a couple team members thought it would be *awesome* to cut a wire and run it as a V6 tach. Screw the 14 hr race, as long as it looks cool for in-car video to have the tach at 8k  

[bennybigb]

10 hours ago, Dcwilliams00 said:

bennybigb....engine swap. Have you ran the 22 yet?

 

Yes, we ran the car at Gingerman this past weekend.  The car is very experienced, having ran with NASA on the West Coast for quite some time and it was originally a Long Beach Pro Celebrity car 35 years ago.  It's always had the 22r motor, but it's never done any endurance racing, mostly track days. 

 

I'm wondering if we need a different platform for endurance racing, the car is also not very quick.  We were managing 2:02s at Gingerman, which would put us precisely dead last in the field, by a pretty big margin.

[Ron_e]

If you are DFL then the biggest improvement you can probably make is working on your driving, no offence meant.  

[Ham Sammich]

[Andrew D Johnson]

9 hours ago, bennybigb said:

 

Yes, we ran the car at Gingerman this past weekend.  The car is very experienced, having ran with NASA on the West Coast for quite some time and it was originally a Long Beach Pro Celebrity car 35 years ago.  It's always had the 22r motor, but it's never done any endurance racing, mostly track days. 

 

I'm wondering if we need a different platform for endurance racing, the car is also not very quick.  We were managing 2:02s at Gingerman, which would put us precisely dead last in the field, by a pretty big margin.

 

It sounds like the car is pretty darn cool, and has a sweet history. One of the really cool things about the current chump rule package is how straight forward engine swaps are. I googled your car and saw swaps like 5M-GE from the Celica Supra are common and would get you up around 160HP.

 

After you see how the Gingerman race goes maybe look into swap options. You certainly do not need to change platforms though. 

[Dcwilliams00]

11 hours ago, bennybigb said:

 

Yes, we ran the car at Gingerman this past weekend.  The car is very experienced, having ran with NASA on the West Coast for quite some time and it was originally a Long Beach Pro Celebrity car 35 years ago.  It's always had the 22r motor, but it's never done any endurance racing, mostly track days. 

 

I'm wondering if we need a different platform for endurance racing, the car is also not very quick.  We were managing 2:02s at Gingerman, which would put us precisely dead last in the field, by a pretty big margin.

Is it a GT or GTS? I cannot remember if the 82 offered the GTS. IF it is, it can handle. If its not, swap to an IRS from a GTS or Supra. Here is my build on CelicaSupra for my 85 GTS.

[bennybigb]

All of this information is great guys!  Thank you!

 

The car is the only the GT, so no IRS but the car does handle pretty well currently. 

 

I am also on CelicaSupra and I think I may have browsed your build history, but I'll look at it again.  I was surprised that more people don't race these things, but now I've learned why!

[Dcwilliams00]

2 hours ago, bennybigb said:

All of this information is great guys!  Thank you!

 

The car is the only the GT, so no IRS but the car does handle pretty well currently. 

 

I am also on CelicaSupra and I think I may have browsed your build history, but I'll look at it again.  I was surprised that more people don't race these things, but now I've learned why!

Yeah, the engine. You have the smaller diff  and solid axle also.  But several people race them, just need to do a few things. And if you want overall competitiveness, need to swap that bad boy out. Good thing is that the 22r can go some some money.

Edited July 5, 2017 by Dcwilliams00

[lenbo211]

On 7/4/2017 at 6:55 AM, mender said:

For the most part, a mechanically sound engine can run at or near its design limits for extended time as long as it is kept at the correct operating temperature and the oil pressure is at 8.5 to 10 psi  per 1000 rpm.

 

In other words, keep it cool and supplied with good oil and don't overrev it and it shouldn't blow up.

 

Downshift revs should be as low as possible. Don't use the engine as a brake. When I watch a video I listen to the engine rpm when the throttle is picked up coming out of the corner; done properly, engine rev matching should have the engine very close to the same rpm. I do my downshifting as late as possible, just before needing to get back on the throttle and that keeps the engine abuse and extra fuel usage to a minimum.

 

The old-school redlining of the engine on every downshift sounds racy but does nothing except put the engine at unnecessary risk.

I agree with all of this.

A couple caveats. 

1. Have you had a professional rebuild the motor? If so, ask them.  If not, I'd use the RPM target mentioned in this thread earlier.

2. Dyno the sucker and look at where your curve shows you stop making power.  Reving much past that has diminishing returns and just wears out the motor.

Short shift and use better driving to get lap times rather than relying on high RPM to do it.

Granted, I have a 302 Ford, but my teams best times have always been set by the guys who shift 500 RPM before the shift light comes on.

My builder said I could take mine to 6,500 without worry, but suggested for endurance I keep it to 6,000 or below. I set my shift light at 5,500 and rev limit at 5,900. best lap times are consistently set by the guys who shift at 5,400. 

 

A couple other points.  NEVER use the engine to slow the car down. That will destroy the engine faster than any acceleration over rev. Engines are built for positive torque on the components, but don't handle negative torque on components very well.  (and will destroy the car faster when you end up in the wall when you lock up the wheels) Engine's only purpose is for acceleration.  Brakes are for slowing.

If you're good at rev matching through Heel/Toe, that's the closest thing I'd do to getting near red line.  If you're not good at heel/toe, then just set your idle higher so it only drops so low.   Lazy man's rev match.

[mender]

23 minutes ago, lenbo211 said:

If you're good at rev matching through Heel/Toe, that's the closest thing I'd do to getting near red line.

My philosophy is to concentrate on getting the braking done correctly then get ready for corner exit as I'm getting to the end of the braking zone. To do that, I shift directly to the gear I know I'm going to be in for corner exit as I'm easing out of the brakes, rev-match then get back on the throttle for the exit.

 

With my technique, the rev-matching is never near the redline. It's very close to the rpm that I'll be accelerating out of the corner at, and if that's near the redline, I'm using the wrong gear.
 

[lenbo211]

1 minute ago, mender said:

With my technique, the rev-matching is never near the redline. It's very close to the rpm that I'll be accelerating out of the corner at, and if that's near the redline, I'm using the wrong gear.

Not sure I was being very clear.  What I mean by Heel/Toe being closest I get to red line is the throttle blip. Not all of us are as good and precise as you  and our blip may go a little higher in the rpm range.

[mender]

I don't blip the throttle, I roll my foot to put steady pressure on the throttle to bring the rpm around 3500-4000 rpm and time my shift to make use of that. Cheating but it works for me.

 

I learned that way back when I was running Formula Ford with a crash box, initially double-clutching and blipping through all the gears like I was taught but very quickly switched to my method which allowed much steadier brake pedal pressure, and predictable shift points. Following that, I then went to direct shifting, leading to even less distraction from braking.

 

Most people can't tell when I'm downshifting or even when I pick up the throttle because it's very non-intrusive. For me, that's mission accomplished.

[zack_280]

58 minutes ago, lenbo211 said:

NEVER use the engine to slow the car down.

I don't know if I understand this statement.  Any time you lift off of the throttle on a fuel injected car, the ecu stops injecting fuel and some of the energy of the drivetrain is absorbed by the engine.  Effectively providing some braking via the engine.  My interpretation of the statement is that you should always push in the brake and the clutch at the same time while slowing down, then select the optimum gear and lift off of the brake and clutch while matching revs and start accelerating.  Is that the correct interpretation?  

Edited July 5, 2017 by zack_280

[mender]

I'll jump in and say no. Old-school race cars had poor brakes and had to use engine braking to help the brakes by doing redline downshifts through all the gears. There's no need for that today and it messes with the brake bias, usually making for longer braking zones.

 

Leaving the car in gear when you let off does slow the car somewhat but has minimal effect compared to the old-school rod-strechers.

 

Also:

"Carroll Smith noted that studies of professional drivers' brake pedal pressure showed that even the best heel and toers reduce their pedal pressure during the heel/toe shift. The more gears you row through the longer the time spent with reduced brake pedal pressure and the longer the stopping distance."

Edited July 5, 2017 by mender