Ridiculous boost creep on GT28RS turbo?? - Page 3 - LotusTalk - The Lotus Cars Community

LinkBack Thread Tools Display Modes
post #41 of 49 (permalink) Old 12-31-2012, 03:15 PM
Plug Whisperer
turbophil's Avatar
Join Date: Dec 2005
Location: Kansas City/ Overland Park
Posts: 6,021
The problem is this business about 7psi. If the goal is to run 7psi, a turbo is the wrong tool for the job. Set the gate back up correctly and run 10psi like you should. The motor is fine at that power and boost level if tuned correctly. May or may not be able to run optimal timing but it is what it is. 7 psi isn't going to happen correctly... Nor should it....

My 2 cents

Phil: NASA 2012 and 2014 TT1 Central Champion, 2005 GG Elige, Rev400, 400+whp

2011 Pearl White Evora, BOE Skunk Works || 2005 GG Elise, Rev400, Street Car || 2006 CO Elise, Rev400, Steet Car


www.boefab.com: We Build Champions | Products-Service-Advice

BOE ClamHinge | BOE TVS SuperCharging, The Most Powerful Track-Worthy Forced Induction | EFI Engine Management | BOE The Essential Fuel Starve Solution| BOE Lotus Tow Package| BOE New-Tech Lotus Race Engines | The Right Oil Filter for Your Lotus | Custom Lotus ECU Tuning

Pain makes man Think. Thinking makes man Wise. Wisdom makes tracking a Lotus Endurable
turbophil is offline  
Sponsored Links
post #42 of 49 (permalink) Old 12-31-2012, 03:23 PM Thread Starter
Registered User
wek120's Avatar
Join Date: Mar 2011
Location: NC
Posts: 782
Originally Posted by ageshelin View Post
The porting of the internal W/G is almost sufficient to control boost down to 7psi.
When I say it reaches 7psi, I mean the fuel cut we have placed to avoid blowing past that. In higher gears, it reaches the fuel cut in a split second.

I don't see how you can say creeping all the way up to 7 is to be expected. Even with the wastegate wide open, it still hits that fuel cut like a wall in maybe a second. Wastegate connected, it hits that even faster, as if the thing is welded shut.

Even with overly retarded ignition timing, I wouldn't think it could creep that much... The inital tuning was done by Forged Performance, so I don't see how it could be all that off anyway. Does anyone have an ignition map I could compare with to double check?

Phil; I though most of the FF kits run at about 7psi to start with. When talking with JP at Radium, he suggested 7 as a good place to stay, and 9psi as pushing it. The problem though is not the amount of boost, but the rate it creeps. In say 3rd gear, if you give it 100% throttle, it will hit that fuel cut in a split second, wastegate arm wide open.

With the rate it shoots up to 7, there is no way it would level out at 9 or 10.. (see below)
Attached Images

Last edited by wek120; 12-31-2012 at 04:31 PM.
wek120 is offline  
post #43 of 49 (permalink) Old 01-02-2013, 04:30 PM
Registered User
kverges's Avatar
Join Date: Feb 2005
Location: Dallas
Posts: 1,316
FWIW I successfully control to 8 -9 psi, have run the car on track, but do use Water/methanol injection and race fuel on track. My manifold is crappier, too, so that may help in a twisted way
kverges is offline  
post #44 of 49 (permalink) Old 01-02-2013, 08:26 PM Thread Starter
Registered User
wek120's Avatar
Join Date: Mar 2011
Location: NC
Posts: 782
Yea I wasn't really planning on using meth injection, and also didn't want to destroy the rest of the car (clutch, trans, ect) before I have a chance to build it up, so I think 7psi is a good safe place to start at.

Pulled the exhaust side yet again and ported the crap out of it. Hole is slightly bigger than 1.14" and inlet side has much more material removed on the internal side. Put it back together and took it for a spin, finally with a little success. Wastegate disconnected builds boost only to 3psi, and arm connected levels out around 5, though still with a bit of creep once it gets there. I figure with final tuning it will eliminate whats left. Now on to tackle the clutch slipping problem

For others with a similar problem, I would recommend just getting the housing with the external flange and avoid the headache. I will probably end up picking one up in the future anyway, as that particular housing flows better (higher A/R) and should eliminate any hint of boost creep.
wek120 is offline  
post #45 of 49 (permalink) Old 01-12-2013, 11:41 AM
Registered User
Join Date: Dec 2009
Posts: 76
Boost under control with recommended porting...

Glad to see you were able to accomplish the goal.

As Casey indicated in an earlier post, you can swap out for the housing with external gate, but what did not get mentioned is the amount of additional hot hardware this adds to the installation below the clam. You can do everything you need with what you now have.

The reason that I designed this system to utilize the tidy and reliable Garrett factory internal WG was not cost; it keeps all the exhaust gasses traveling in a nice, condensed path that keeps the overall heat radiation to a minimum. This Is a very important point to consider on these cars. They do not like lots of heat back there. As well, we really try hard to keep the weight down back there... It pays dividends in terms of handling.

When you get ready to build that longblock with forged lower compression pistons, turn that thing up to 12-14 lbs and HANG ON! And if you find you are after more, check out our wet intercooler upgrade that will handle up to 450hp track cars. We can convert your current air to air FF IC for a very reasonable fee. Kris at DRS is a good contact point as he has done a lot with the DMC water/air retrofit with big results.


DMC Comp is offline  
post #46 of 49 (permalink) Old 01-12-2013, 06:41 PM Thread Starter
Registered User
wek120's Avatar
Join Date: Mar 2011
Location: NC
Posts: 782
To reduce all the heat, I've wrapped and thermal sprayed the headers, wrapped the upper portion of the exhaust, and covered the turbo with a PTP turbo blanket. You can practically rest your hand on the turbo blanket when hot and touch the headers for a sec without getting burned. Took temps way down, I'd suggest anyone having problems with heat to do the same.

Jim, any suggestion on a good number to keep the boost below to avoid blowing the stock motor on track? (without running meth or race gas)

Last edited by wek120; 01-12-2013 at 06:47 PM.
wek120 is offline  
post #47 of 49 (permalink) Old 01-20-2013, 01:01 PM
Registered User
Join Date: Dec 2009
Posts: 76
Yeah Wes, it really depends on what kind of engine management you are using; I've seen poor ECU solutions kill engines with 5 or 6 psi in the heat. They just do not take into account enough tuning factors.
On the other hand, with really good engine control using speed/ density, a sharp tuner and good fuel, I have actually run the dead stock 2ZZ with cast pistons all day long at 10 psi boost. Not for everyone, but it has been done with success.

For a modified stock ECU car, I could not recommend more than 7 or 8 and pay close attention to the amount of crankcase pressure generated. A really good sized vent and catch can is mandatory. Cooler heat range plugs are important also.

If you are tracking the car or live in the southern climates where it gets hot, consider converting your IC to water to air cooling. It makes a really big difference in terms of lowering intake temps while doing a lot of full boost track running. And of course this converts directly to longevity and horsepower.

I have seen more than a couple 2ZZ engines detonate while running too much timing and just throw the #4 rod out after spinning the rod bearing. Rattling these engines usually results in sudden death at higher rpm/ power levels, so excercising caution is always a good default.

Hope this helps and have fun beating up N/A cars out there!

DMC Comp is offline  
post #48 of 49 (permalink) Old 01-22-2013, 09:00 PM
Registered User
Join Date: Jul 2012
Posts: 19
I feel compelled to post because of my personal journey with the FF275 kit. When I purchased the car it already had the FF275 kit on it. Due to stress on the manifold caused by a misaligned exhaust and excessive weld heat from a poorly executed EGT bung the manifold decided to let go shortly thereafter.

Long story short, I got ahold of Jim of DMC and he was able to rebuild and strengthen the manifold for a very reasonable cost, on the original jigs, and with a custom EGT bung to replace the original hack job. He added gussets to the flange which were an update to the later FF manifolds. The manifold was ceramic coated and he provided new hardware for it to all go back together. Here is the "after" photo and the craftsmanship is impeccable.

So, Jim does really great work. I'm not sure what happened before but I thought I would post my data point as a reference. (within the last 3 months btw)

The car is still being tuned but it's getting close. Here is my boost curve for comparison to yours. The car was running a bit rich and the RPM trace is wonky but you get the idea.

OP, I'm not experiencing boost creep since I'm running at a higher boost level than you. Usually when I experience boost creep I don't try to fight it...rather I just turn up the boost a bit Glad you solved your issue.

We should compare maps sometime =)
Nocturnal005 is offline  
post #49 of 49 (permalink) Old 01-28-2013, 09:38 AM
Registered User
Join Date: Dec 2009
Posts: 76
Nice installation...

Hey Nocturnal,

Thanks for the kind words.

As some may know, I am a one man band and thus am limited on my output; I have a day job, so building parts can place quite a demand on my time. I try to accomodate everyone, and always strive to build DMC Components as the best quality parts you can buy. Unfortunately, this takes time and as a result I have been guilty of missing deadlines on more than one occasion. I am truly sorry about any misunderstandings that may have occured in the past.

The pictures of your install look great!

Your manifold was the second one that has failed since we have been building them starting in 2005; Yours and the other one were early ones that did not include the gusseting updates that started after serial # 351, and had a very poorly executed (by some else) O2 bung welded in after production. That ultimately spelled disaster. Very glad to have been able to restore yours, and include the updates and coating. I offer this service to anyone that has our early manifold and I do it very reasonably. We have a lot of these manifolds (over 150) in service around the world and many have over 100,000 miles on them still going strong. They are all 321 stainless - not 304. Expensive but the only material to use in this application in my experience.

I have been caught up for about six months now, so I have been able to keep my shipments current and keep those in need supplied with the right stuff.

We have developed a very nice air to water conversion for the FF 275 and 380 packages. This update utilizes the current air to air core so it is surprisingly cost effective, and we do it on an exchange basis. Even on the lower boost cars, the air/water conversion really helps out with power, especially on track cars and ones running in the heat. It makes the tuning much more consistent, almost completely eliminating heat soak. Kris at DRS has used several of these intercoolers to generate as much as 480 HP with air intake temps of 100 degrees or less!

You can see his posts here or go to DRS website to see his results; they are impressive.

Have a ball with that Lotus of yours, should be a handful on open track days!!!!

DMC Comp is offline  
Sponsored Links

  LotusTalk - The Lotus Cars Community > Lotus Discussions > Powertrain (Engine, Transmission, etc) > Forced Induction

Quick Reply

Register Now

In order to be able to post messages on the LotusTalk - The Lotus Cars Community forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:


Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

For the best viewing experience please update your browser to Google Chrome