R/C Tech Forums

Go Back   R/C Tech Forums > General Forums > Nitro Off-Road

Reply
 
Thread Tools Search this Thread
Old 02-19-2009, 06:03 AM   #46
Tech Regular
 
lowey79's Avatar
 
Join Date: Dec 2007
Posts: 356
Default

Ok, i thought i'd bring back an old thread rather than start a new one... I see there are varied opinions on the GRP vs V-Spec topic... My question is, is there anyone who can give me a comparison between a GRP 21MRT and an OS Speed? I've been running a speed for about a year now, (I have 2 actually) but i was interested to try the tuned GRP.... Any thoughts?

Cheers....TIA!
lowey79 is offline   Reply With Quote
Old 02-19-2009, 06:20 AM   #47
Suspended
 
Join Date: Jan 2007
Location: VA
Posts: 10,180
Trader Rating: 440 (99%+)
Default

Quote:
Originally Posted by desertbird View Post
Yeah I am now hearing that the GRP is a PITA to keep in tune... Guess I'll learn to be a great tuner with this thing... if I don't huck it over the fence first because is pisses me off everytime I have a heat and it needs a complete retuning.
The GRP is no harder to tune than any other engine. Run a small idle gap, a lean bottom end and a fat top. DON'T TUNE TO TEMP either because they like to run cool. And tuning to temp is not the way to go for any engine.
MattP is offline   Reply With Quote
Old 02-19-2009, 06:44 AM   #48
Tech Elite
 
Join Date: Aug 2007
Location: Birmingham Alabama
Posts: 4,835
Trader Rating: 24 (100%+)
Default

Quote:
Originally Posted by ezveedub View Post
All I can say is, the GRP got so much attention due to a lot of US drivers using them. At our local track, the OS is the choice to use. Very few use the GRP and even at that, I have seen some have issues with it and it hasn't had any performance to write home about

If I wanted an italian mill, Novarossi would have been my choice. GRP & Axe Rossi are family member spinoffs, but they have some engine goods traits in their engine building IMO. GRP just got on to a bigger distrubutor than Axe Rossi did. But at least Axe Rossi brought a EUROs title to their brand name.
I think it's all in the drivers in your local area. The fastest guys in florida are sponsored by someone else other than GRP, so obviously they run whatever it is they are sponsored by. Or, you may have die hard Nova or OS guys and then they crowd sways that way. Truth is we have a great choice of .21 engines on the market today.

In my area since I run GRP a lot of racers have now switched to GRP. They have someone to help them at all the races tune, etc. They love them. The OS is a great engine but without a doubt the rod and crank pin last much longer on the GRP's. It is my experience that the GRP gets some of the best fuel mileage out there today. It's really a good mill, with deceiving power. It's smooth and lays down the power very well. It may not sound as fast as a OS or NOvarossi, but if tuned correctly on any straight you go down with another mill will show you different.

I'll tell you guys something that I feel makes it more than worth it to run a grp over any engine out there. Once it's time to start thinking about a new p/s on your engine you can send it back to horizon hobbies in ontario, ca(attention adam drake), along with two fresh bearings, and Adam/Horizon will install your bearings and give your sleeve a fresh pinch all for no charge. This gets you a fresh engine that's ready to go for another few gallons. A few of my local guys have done this and for about $50-60(cost of bearings and shipping) you have a fresh engine. MAke sure to include your contact info with it.
__________________
Owner of the Speed Shop: A race prep shop for anything related to 1/10 and 1/8 off road racing. Check us out: https://www.facebook.com/pages/The-Speed-Shop/382214705269137?ref=bookmarks
ABURTON is offline   Reply With Quote
Old 02-19-2009, 07:18 AM   #49
Tech Addict
 
desertbird's Avatar
 
Join Date: Apr 2008
Location: Surprise, AZ
Posts: 551
Trader Rating: 7 (100%+)
Default

Quote:
Originally Posted by ABURTON View Post
The OS is a great engine but without a doubt the rod and crank pin last much longer on the GRP's.
Well, after about 2 gallons on mine the bottom of my con rod fell off rendering the whole engine useless

I bought GRP because of longevity claims. Broke it in heat cycle method by the bible. Always ran with good smoke stream. To have that happen, along with the fact that I could never find bottom end in my TRUGGY. I went with something else.

NOW, there are plenty of happy GRP owners, it IS a good engine, but I will never run one again unless its a screaming deal, and for truggy I'd go with a .28.
desertbird is offline   Reply With Quote
Old 02-19-2009, 05:31 PM   #50
Tech Lord
 
Frank L's Avatar
 
Join Date: Dec 2008
Location: NorCal
Posts: 12,500
Trader Rating: 148 (100%+)
Default GRP all the way

I have run a GRP .21 tuned version in an 8T for the last race season with very little problems. I did notice a little lack of torque in the heavy truggy but I upped the spring rate in the clutch and went to a long header to max out the torque and was pleased with it. I have recently purchased a powerhouse race modded GRP .21 non tuned and this motor smokes the tuned version in performance and mileage. I average 11.5 min per tank which is +1 min longer than the tuned version and I donít see any issue with not enough torque. I did switch to an 8T 2.0 and even used the stock spring setup of gold and green which is much weaker than the all silver spring setup I was running before. I will have to see if it lasts like the tuned version. I had 6-6.7 gal on the tuned version and it was still running strong. I replaced a front bearing at 5 gal and thatís it. I have sold the tuned version so no more comparison but I am sending a new GRP .21 tuned version to powerhouse for their turbo mod. I am sure I will be happy with it. I have run an OS V-spec and it did not make it past the 5 gal mark. The compression was gone and the front bearing was gone too. Tune was not difficult just donít touch the middle needle ever. If you do you will wish you never did, there is no going back after you touch the middle needle. GRP gets my vote I will prob buy a 4th.
Frank L is offline   Reply With Quote
Reply

Similar Threads
Thread Thread Starter Forum Replies Last Post
opinions please! which is better the o.s speed vspec or the eb modded vspec? downunder23 Offroad Nitro Engine Forum 23 11-29-2015 02:37 PM
RB .15 VSpec Squackyrc Australia For Sale/Trade 0 08-21-2008 05:23 AM
FS: EB Mod OS Vspec BH R/C Items: For Sale/Trade 4 10-18-2007 07:00 AM
NIB 07 EB Mod VSpec Cyberacer R/C Items: For Sale/Trade 4 09-13-2007 06:51 PM
NIB 07 VSPEC....$245 ckt111 R/C Items: For Sale/Trade 5 08-30-2007 05:38 PM



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not 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 Off



All times are GMT -7. It is currently 02:47 PM.


Powered By: vBulletin v3.9.2.1
Privacy Policy | Terms of Use | Advertise Content © 2001-2011 RCTech.net